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The emergence of SARS-CoV-2, responsible for coronavirus disease-2019 (COVID-19), has become a major global health problem. The molecular testing is the accepted assay in SARS-CoV-2 detection. However, there are several reasons for low sensitivity by RNA detection, causing challenges in SARS-CoV-2 diagnosis. In this study, we aimed to investigate serological patterns of SARS-CoV-2 specific IgM, and IgG in 111 hospitalized, and 34 recovered COVID-19 patients and 311 prepandemic normal serum specimens by ELISA. The validity of the ELISA kits was evaluated using samples from normal and recovered cases. This showed that 98.1%, and 98.4% of prepandemic normal samples were negative for anti-SARS-CoV-2 IgM, and IgG, respectively. Assessment of 34 COVID-19 confirmed recovered patients showed a test sensitivity of 76.5%, and 94.1% for IgM, and IgG, respectively. In COVID-19 hospitalized patients, 42.3%, and 51.4% were positive for IgM and IgG, respectively. Viral RNA was not detectable in 43.3% of the hospitalized patients. Interestingly, combined molecular and serological testing improved the sensitivity of COVID-19 diagnosis to 79.6%. Using PCR with combined IgM/IgG results augmented the patient diagnosis sensitivity to 65.3% and 87.2% in ≤ 7 days, and > 7 days intervals, respectively. Overall, serological tests in combination with PCR can improve the sensitivity of COVID-19 diagnosis.

Hydatid cyst disease is a parasitic infection caused by larval stage of Echinococcus granulosusaffecting mainly the liver. Diagnosis of hepatic hydatidosis depends on clinical presentations, serologicalassays and radiological findings. The present study included 40 patients suffered fromhepatic hydatid cysts. They were classified into 4 groups according to therapeutic protocols theyreceived. All cases were subjected to serological assay, radiological examination to categorizecysts and open surgical intervention for treatment. Samples of hydatid fluid and cysts were examinedregarding parasitological, morphometric and histopathological aspects. Viability of cystcontents was assessed using eosin stain. All samples were cultivated for microbiological assessment.Viability was 95-100% in GI (no previous treatment), 50-85% in GII, 25-45% in GIII(single PAIR technique and single Albendazole course) and 0-10% in GIV (repeated PAIR andmedical treatment). Enterococci and Staphylococcus aureus were detected in one samplein GI and 8 samples in GIV respectively.

The ability to rapidly diagnose, track, and disseminate information for SARS-CoV-2 is critical to minimize its spread. Here, we engineered a portable smartphone-based quantum barcode serological assay device for real-time surveillance of patients infected with SARS-CoV-2. Our device achieved a clinical sensitivity of 90% and specificity of 100% for SARS-CoV-2, as compared to 34% and 100%, respectively, for lateral flow assays in a head-to-head comparison. The lateral flow assay misdiagnosed ∼2 out of 3 SARS-CoV-2 positive patients. Our quantum dot barcode device has ∼3 times greater clinical sensitivity because it is ∼140 times more analytically sensitive than lateral flow assays. Our device can diagnose SARS-CoV-2 at different sampling dates and infectious severity. We developed a databasing app to provide instantaneous results to inform patients, physicians, and public health agencies. This assay and device enable real-time surveillance of SARS-CoV-2 seroprevalence and potential immunity.

Background The detection of antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is mandatory for the diagnosis, retrospective assessment of disease progression, and correct evaluation of the current infection situation in the population. Many such assays have been launched by various manufacturers. Unfortunately, the new US Food and Drug Administration emergency use regulations have resulted in a situation where laboratories have to perform their own validation studies but many of these laboratories do not have the biobank needed to conduct the studies. Methods We introduce a method that allows institutions to quickly perform a verification study in a low-prevalence infection situation. As proof of concept, we used the Roche Elecsys® anti-SARS-CoV-2 electrochemiluminescence immunoassay and an SAP-based hospital information system. The Shenzhen YHLO Biotech IgM and IgG assay targeting other surface patterns was used as a confirmatory test. Results The Roche assay demonstrated a limit of detection of 0.069 cutoff index and successfully passed the performance validation according to Clinical and Laboratory Standards Institute EP15-A3. The study population of 627 inpatients has a median age of 64 years, and approximately 13% of the group were under intensive care at the respective time point. All patients included tested negative for SARS-CoV-2 infection by quantitative reverse transcription polymerase chain reaction (cobas® 6800, Roche, Mannheim, Germany). Only one false-positive result was obtained, resulting in a specificity for the Roche Elecsys anti-SARS-CoV-2 test of 99.84% and a negative predictive value of 99.98%. Conclusions The anonymized use of residual material enables quick evaluation of anti-SARS-CoV-2 immunoassays, as shown in this work with the Roche Elecsys assay. Comparison of the control population with economic data makes it possible to validate the sampling set and therefore to determine diagnostic specificity. By use of the approach chosen, it was shown that the Roche test achieved very good results in terms of diagnostic specificity, reproducibility, and limit of detection.

Zika virus (ZIKV) has emerged as a particularly notorious mosquito-borne flavivirus, which can lead to a devastating congenital syndrome in the fetuses of pregnant mothers (e.g., microcephaly, spasticity, craniofacial disproportion, miscarriage, and ocular abnormalities) and cause the autoimmune disorder Guillain-Barre' syndrome of adults. Due to its severity and rapid dispersal over several continents, ZIKV has been acknowledged to be a global health concern by the World Health Organization. Unfortunately, the ZIKV has recently resurged in India with the potential for devastating effects. Researchers from all around the world have worked tirelessly to develop effective detection strategies and vaccines for the prevention and control of ZIKV infection. In this review, we comprehensively summarize the most recent research into ZIKV, including the structural biology and evolution, historical overview, pathogenesis, symptoms, and transmission. We then focus on the detection strategies for ZIKV, including viral isolation, serological assays, molecular assays, sensing methods, reverse transcription loop mediated isothermal amplification, transcription-mediated amplification technology, reverse transcription strand invasion based amplification, bioplasmonic paper-based device, and reverse transcription isothermal recombinase polymerase amplification. To conclude, we examine the limitations of currently available strategies for the detection of ZIKV, and outline future opportunities and research challenges.

Introduction Pulmonary tuberculosis (PTB) is the most common form of tuberculosis. In Nigeria, PTB is diagnosed by sputum smear microscopy. The problems associated with the diagnosis of PTB using sputum smear for acid-fast bacilli and culture has provided an urgent need to assess the utility of serological tools as an adjunctive diagnostic tool in presumptive PTB cases. This study is aimed at testing the diagnostic utility of a specific immunoglobulin G (IgG) serological assay in the diagnosis of PTB. Patients and methods A utility study was conducted on 184 participants of which 92 were smear-positive PTB cases and 92 were healthy controls at the TB and Leprosy Centre and Ahmadu Bello University Teaching Hospital, Zaria. Data were collected on age and sex, and both PTB patients and controls were screened for anti-TB IgG antibodies by enzyme-linked immunosorbent assay technique. Results The mean age of the participants was 35, and the male-female ratio was 1 : 4. Twenty-one (5.7%) of the PTB patients tested positive for IgG antibodies, and 11 (1.3%) of the controls were positive. The sensitivity of the IgG antibody assay was 18.4%, with the specificity being 92.3%, while the predictive values were 70.8 and 53.1% for positive and negative results, respectively. Conclusion The IgG antibody assay is poorly sensitive; serology may not have a role in the diagnosis of PTB in resource-limited settings, but the much higher specificity suggests that it may be useful as an adjunctive diagnostic tool, or for monitoring of patients on treatment for PTB.

Background: Cystic echinococcosis is a frequent worldwide disease. Surgery is the main policy oftreatment. The benzimidazoles are the drugs of choice as adjuvant therapy besides surgery, but they havesome drawbacks, so there is a pressing need to develop other safe and cheap drugs such as an herbalextract.Objectives: To increase the efficacy of Nigella sativa oil (NSO) administered either as monotherapy orcombined with albendazole, and using chitosan nanoparticles as a drug delivery system for both drugs.Material and Methods: E. granulosus protoscoleces were obtained by aseptic puncture of hydatidcysts. Mice infected by intraperitoneal inoculation with nearly 1000 protoscoleces per mouse weresubdivided into 7 groups: G2, infected non-treated; G3, treated with albendazole; G4, treated with NSO;G5, treated with NSO and albendazole; G6, treated with albendazole loaded on chitosan nanoparticles;G7, treated with NSO loaded on chitosan nanoparticles; G8, treated with albendazole and NSO loaded onchitosan nanoparticles. G1 included the non-infected, non-treated control mice. Serum was collected forbiochemical and serological assay. NO was measured according to nitric oxide assay colorimetric kit. Thesystemic level of TNF-α and IL-5 was determined in the plasma of mice using commercial enzyme-linkedimmunosorbent assay kits.Results: The results revealed that a significant increase of IL-5 occurred in all treated groups to reach thehighest value in G8. There was a significant decrease of TNF-α in all treated groups in comparison to G1and G2 (P

This retrospective study evaluated the reactivity of 3 human immunodeficiency virus (HIV) confirmatory assays (INNO-LIA, Geenius, and MP) and 7 HIV rapid tests on samples from 2 different study populations in Belgium. For the early-treated cohort (83 HIV-1 adult patients treated within 3 months after infection), HIV-1 diagnosis was not obtained in at least 1 confirmatory assay in 12.0% (10/83) and in an HIV rapid test in 31.3% (26/83). Confirmation assay sensitivities ranged from 87.5% to 95.2%, whereas rapid test assay sensitivities ranged from 75.9% to 100%. The time to treatment initiation or the length of time on treatment did not have a statistical influence on the probability to obtain a false-negative test result. The fastest reversion was demonstrated after 4 months of treatment. Among the long-term treated cohort (390 HIV-1 patients with ≥ 9 years of undetectable viral load), false-negative test results were found in at least 1 HIV confirmatory assay for 2.1% (8/390) of the patients and in a HIV rapid test for 4.9% (19/390). Confirmation assay sensitivities ranged from 98.1% to 99.5%, whereas rapid test sensitivities ranged from 96.2% to 100%. Longer treatment increased nonreactivity of the HIV rapid tests (P = .033). Undetectable viral load decreases the sensitivities of HIV diagnostic tests, and further monitoring of the performance of serological assays is advised. ispartof: JOURNAL OF INFECTIOUS DISEASES vol:222 issue:10 pages:1660-1669 ispartof: location:United States status: published

SARS-Cov-2 (severe acute respiratory disease coronavirus 2), which causes Coronavirus Disease 2019 (COVID19) was first detected in China in late 2019 and has since then caused a global pandemic. While molecular assays to directly detect the viral genetic material are available for the diagnosis of acute infection, we currently lack serological assays suitable to specifically detect SARS-CoV-2 antibodies. Here we describe serological enzyme-linked immunosorbent assays (ELISA) that we developed using recombinant antigens derived from the spike protein of SARS-CoV-2. Using negative control samples representing pre-COVID 19 background immunity in the general adult population as well as samples from COVID19 patients, we demonstrate that these assays are sensitive and specific, allowing for screening and identification of COVID19 seroconverters using human plasma/serum as early as two days post COVID19 symptoms onset. Importantly, these assays do not require handling of infectious virus, can be adjusted to detect different antibody types and are amendable to scaling. Such serological assays are of critical importance to determine seroprevalence in a given population, define previous exposure and identify highly reactive human donors for the generation of convalescent serum as therapeutic. Sensitive and specific identification of coronavirus SARS-Cov-2 antibody titers may, in the future, also support screening of health care workers to identify those who are already immune and can be deployed to care for infected patients minimizing the risk of viral spread to colleagues and other patients.

Summary Severe fever with thrombocytopenia syndrome (SFTS), a tick-borne infectious disease with high mortality, is diagnosed by the serological testing of serum samples from patients in the acute and convalescent phases and/or by direct detection of the SFTS virus (SFTSV). Conventionally, heat and UV treatments have been used to inactivate the viruses present in serum samples before performing the serological assays. Here, we examined the inactivation conditions optimal for SFTSV-containing serum samples to ensure the safety of laboratory workers while maintaining the accuracy of serological assay results simultaneously. Heating human serum samples spiked with SFTSV to 60 °C for 30 min or exposing them to UV irradiation for 30 min, reduced the infectious virus titer below the limit of detection. SFTSV in sera from patients in the acute phase of SFTS was completely inactivated by heating to 60 °C for 30 min, followed by UV irradiation for 10 min. This inactivation procedure had minimal impact on the performance of SFTSV antibody detection tests. The data provided herein can serve as a guide for laboratory workers and researchers working with SFTS serological tests.

This letter takes a cue from a recently published study, which looked at diagnostic tests currently available for SARS-CoV-2 infection, to present and discuss the results of a re-evaluation of 122 positive serum samples from COVID-19 patients using an in-house serological assay for SARSCoV-2 antibodies detection. While serology targeting the SARS-CoV-2 S protein should be preferable, IgA testing is proposed in all situations for which serology is the solely practicable diagnostic strategy for SARSCoV-2 infection.

Objectives: Although in Ukraine the incidence of Lyme borreliosis (LB) has been surging up over the past decades, seroepidemiologic data are not available to date. The objective of this report was to perform preliminary serological survey of hospitalized population for LB. Methods: Sera were collected from 203 patients of a hospital located in Western Ukraine. Most patients showed clinical signs that were compatible with LB such as arthritis (n = 29), neurological signs (n = 35), and erythema migrans (EM)-like lesions (n = 60) or unrelated to LB (n = 79). The specimens were tested by enzyme-linked immunosorbent assay and Western blot for anti-Borrelia antibodies. Results: LB was confirmed in 8.6%, 34.5%, and 50% of the patients, who exhibited neurological signs, arthritis, or EM-like lesions, respectively. Anti-Borrelia antibodies were also detected in 6.3% of the patients with pulmonary tuberculosis. Conclusions: This study provides the first preliminary data on the seroprevalence of LB in Ukraine. Future studies are warranted to investigate more subsets of the Ukrainian population for this emerging tick-borne disease.

Performing a cohort-based SARS-CoV-2 antibody assay is crucial for understanding infection status and future decision-making. The objective of this study was to examine consecutive antibody seroprevalence changes among hospital staff, a high-risk population. A two-time survey was performed in May and October 2020 for 545 hospital staff to investigate the changes in the results of the rapid kit test and chemiluminescence immunoassay (CLIA). The seroprevalence of each assay was summarized at both the survey periods. The proportion of seropositive individuals in the CLIA for each survey period and the number of confirmed COVID-19 cases in Central Fukushima were then compared. We chose 515 participants for the analysis. The proportion of IgM seroprevalence in CLIA increased from 0.19% in May to 0.39% in October, and IgG seroprevalence decreased from 0.97% in May to 0.39% in October. The proportion of IgM seroprevalence in the rapid kit test decreased from 7.96% in May to 3.50% in October, and IgG seroprevalence decreased from 7.77% in May to 2.14% in October. The IgG and IgM antibody seroprevalence among hospital staff in rural Central Fukushima decreased; the seroprevalence among hospital staff was consistent with the number of confirmed COVID-19 cases in the Central Fukushima area. Although it is difficult to interpret the results of the antibody assay in a population with a low prior probability, constant follow-up surveys of antibody titers among hospital staff had several merits in obtaining a set of criteria regarding the accuracy of measures against COVID-19 and estimating the COVID-19 infection status among hospital staff.

Background Fourth-generation immunoassays (such as the ADVIA Centaur® HIV Ag/Ab Combo (CHIV) assay) have improved the early diagnosis of human immunodeficiency virus (HIV), and their sensitivity and specificity usually exceed 99%. In regions with a low prevalence of HIV infection, however, the regular occurrence of false positives interferes with a medical laboratory’s workflow. The additional reagent and staff costs associated with false positives can nevertheless be avoided or reduced by gaining a better knowledge of the CHIV assay’s performance. Objectives/study design To improve our HIV diagnosis strategy, we retrospectively analyzed all the Centaur® CHIV assays and confirmatory tests performed at Amiens University Medical Center between 2012 and 2018. We used open-source machine learning software to process this large database, develop a predictive model, and identify a new cut-off for Centaur® CHIV index interpretation. Results A total of 56,682 HIV serological assay results were analyzed. The results of the CHIV assay were initially reactive or indeterminate for 449 samples. After p24 antigen and/or immunoblotting, there were 171 (38%) false positives and 278 (62%) confirmed true positives. The application of a cut-off of 2.12 led to reclassification of 130 of the 171 false positives as true negatives. Combining our predictive model with medical record analysis reduced the number of false positive CHIV assay results from 171 to 12. Conclusions The efficiency of the Centaur® CHIV assay can be increased by adjusting its cut-off for positivity. This adjustment may reduce the number of unnecessary confirmatory tests and accelerate the delivery of HIV test results.

The prevalence of human taeniasis has decreased in Korea. The stool egg positive proportion decreased from 1.9% in 1971 to 0% in 2004 in nationwide surveys. The neurocysticercosis (NCC) is also presumed to decrease. However, detailed information regarding the recent status of NCC in Korea is lacking. We retrospectively reviewed NCC cases from 1990 to 2016 at Asan Medical Center, a 2700-bed tertiary referral hospital in Korea. We identified patients based on clinical symptoms, brain imaging, pathology and serological assay. The cases were classified as parenchymal, extraparenchymal, and mixed NCC. Eighty-one patients were included in the analysis. The mean age was 54.5 years, and 79.0% were male. The number of NCC cases was highest from 1995 to 1999, and continuously decreased thereafter. Forty (49.4%) patients had parenchymal NCC, while 25 (30.9%) patients had extraparenchymal NCC, and 16 (19.8%) patients had mixed NCC. The seizure and headache were most common symptom of parenchymal NCC and extraparenchymal NCC respectively. Hydrocephalus was more common in extraparenchymal NCC, and patients with extraparenchymal NCC were more likely to require a ventriculoperitoneal shunt. Cases of NCC are decreasing accordingly with human taeniasis and lesion location was the most important determinant of clinical presentation and outcome of NCC in Korea.

Recent data published in the literature reported on the performance of the quantitative Roche Elecsys anti-SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) S assay ([1][1][–][2][3][3]). The specificity of the test was between 99.8 and 100% ([1][1][–][2][3][3]). However, for

Background: Beyond the diagnosis of SARS-CoV-2 infection, tools delivering a global picture of the patients’ humoral response may be of interest for the comprehension of the disease severity and the assessment of the patients’ protection for vaccination strategy. Objectives: Here we use a commercial multiplex serological immunoassay CoViDiag®, based on an array of five different antigens of the virus (the Nucleocapsid, the Spike 1 and Spike 2 subunits, and the RBD and NTD domains of the Spike), to investigate the profile of the IgG humoral response for patients with recent SARS-CoV-2 infection depending on the disease severity outcome, or the time post-PCR. Results: No cross-reaction was observed with the four other seasonal coronaviruses (100% specificity, 0/28). 100% (20/20) of the hospitalized patients PCR-positive to SARS-CoV-2 presented detectable levels of IgGs. 14 days post-PCR diagnosis, 92.3% of the patients, PCR-positive, that did not required hospitalization are presenting IgG (36/39). Interestingly for CoViDiag-positive samples, detectable levels of anti-RBD were found mainly in hospitalized patients (85%, 17/20), while the presence of anti-S1 (60.9%, 28/46) combined with the absence of anti-RBD (6.5%, 3/46) was more characteristic of nonhospitalized patients. Screening campaign group lacked both anti-S1 (18.2%, 4/22) and anti-RBD (4.5%, 1/22). Conclusion: The CoViDiag® IgG assay could be used to evaluate patients’ immunization and improve their management.

The incidence of autism spectrum disorder (ASD) has been rising, however ASD-risk biomarkers remain lacking. We previously identified the presence of maternal autoantibodies to fetal brain proteins specific to ASD, now termed maternal autoantibody-related (MAR) ASD. The current study aimed to create and validate a serological assay to identify ASD-specific maternal autoantibody patterns of reactivity against eight previously identified proteins (CRMP1, CRMP2, GDA, NSE, LDHA, LDHB, STIP1, and YBOX) that are highly expressed in developing brain, and determine the relationship of these reactivity patterns with ASD outcome severity. We used plasma from mothers of children diagnosed with ASD (n = 450) and from typically developing children (TD, n = 342) to develop an ELISA test for each of the protein antigens. We then determined patterns of reactivity a highly significant association with ASD, and discovered several patterns that were ASD-specific (18% in the training set and 10% in the validation set vs. 0% TD). The three main patterns associated with MAR ASD are CRMP1 + GDA (ASD% = 4.2 vs. TD% = 0, OR 31.04, p = p = 0.0005) and NSE + STIP1 (ASD% = 3.1 vs. TD% = 0, OR 22.82, p = 0.0001). Additionally, we found that maternal autoantibody reactivity to CRMP1 significantly increases the odds of a child having a higher Autism Diagnostic Observation Schedule (ADOS) severity score (OR 2.3; 95% CI: 1.358–3.987, p = 0.0021). This is the first report that uses machine learning subgroup discovery to identify with 100% accuracy MAR ASD-specific patterns as potential biomarkers of risk for a subset of up to 18% of ASD cases in this study population.

Visceral Leishmaniasis (VL) is a severe parasitic disease that has emerged as an important opportunistic condition in HIV-infected patients and whose control is impaired by inaccurate identification. This is mainly due to the serological tests used for VL having a reduced performance in cases of VL-HIV coinfection due to a low humoral response. In this situation, however, a positive test has even greater diagnostic value when combined with the clinical status. This study aimed to evaluate the application and performance of flow cytometry to detect anti-Leishmania infantum antibodies in HIV-infected patients. Sera from VL/HIV coinfected patients, characterized using “gold standard” techniques, were compared with sera from healthy controls plus sera from HIV-infected individuals. The flow cytometry results were expressed as levels of IgG reactivity, based on the percentage of positive fluorescent parasites (PPFP). A ROC curve analysis of a serum titration indicated a PPFP of 1.26% as being the cutoff point to segregate positive and negative results. At the 1:2,048 dilution, with 89% sensitivity and 83% specificity, flow cytometry showed greater sensitivity in relation to the serological tests evaluated. Futhermore, flow cytometry was the only assay that positively identified all VL-HIV patients with quantified HIV load. Together, these findings suggest that flow cytometry may be used as an alternative serological approach for VL identification and as a tool to characterize the humoral response against Leishmania infantum in HIV-infected patients.

Objectives To investigate the epidemiological features of diarrheagenic Escherichia coli (DEC) in patients with acute diarrhea in China. Methods An active sentinel surveillance was performed in all-age patients with acute diarrhea in China, 2009‒2018. DEC was isolated and identified by serological assay and PCR from stool samples. Results DEC was determined in 6.68% (6,119/91,651) of the patients, with higher positive rates among females than among males (6.97% vs. 6.46%) and among 18‒59 years patients (7.88%) than among other age groups. Five pathotypes were identified, the most prevalent was enteroaggregative E. coli (EAEC), followed by enteropathogenic E. coli (EPEC), and enterotoxigenic E. coli (ETEC). Pediatric patients

Purpose of the study PCR is the current standard test for the diagnosis of SARS-CoV-2 infection. However, due to its limitations, serological testing is considered an alternative method for detecting SARS-CoV-2 exposure. In this study, we measured the level of SARS-CoV-2 IgM and IgG antibodies of male professional football players and compared the results with the standard PCR test to investigate the association between the two tests. Study design Participants were male professional football players and team officials. Nasopharyngeal swabs and peripheral blood samples were collected for the PCR and serological tests, respectively. Also, previous records of COVID-19 testing and symptoms were gathered. Those with previous positive PCR tests who tested negative for the second time were considered to be recovered patients. Results Of the 1243 subjects, 222 (17.9%) were seropositive, while 29 (2.3%) tested positive for the SARS-CoV-2 PCR test. Sixty percent of symptomatic cases with a negative PCR were found to be seropositive. The mean level of IgM was significantly higher in PCR-positive and symptomatic subjects, whereas the recovered cases showed significantly higher levels of IgG. Conclusion Our study revealed an inconsistency of results between the two tests; therefore, although application of serological assays alone seems insufficient in diagnosing COVID-19 disease, the findings are beneficial in the comprehension and the management of the disease.

PurposeSARS-CoV-2 serology testing is key for assessing seroprevalence and antibody response post-vaccination in immunocompromised patients. Evaluation of current SARS-CoV-2 serological assays have been performed on samples from severe COVID-19 hospitalised patients. However, robust assay development requires assessment in asymptomatic and non-hospitalised individuals to determine if serological assays are sensitive to detect waning and mild antibody responses. Our study evaluated the performance characteristics between two high-throughput SARS-CoV-2 IgG nucleocapsid assays (Abbott and Roche) and The binding site (TBS) Anti-Spike IgG/A/M ELISA kit in healthcare workers.Methods236 samples were collected from Portsmouth Hospital University NHS Trust (PHU) and The Dudley Group NHS Trust and analysed for SARS-CoV-2 serology. We derived concordance, agreement and assay performance as well as using receiver operating characteristic (ROC) curves to redefine the assay threshold of the Abbott assay.ResultsResult concordance between the Abbott and TBS was 66%. Discrepant samples were analysed using the Roche assay which showed 100% agreement with the TBS assay. In samples analysed >58 days post-PCR, the sensitivity of Abbott and Roche was 100%. In samples analysed >100 days post-PCR the sensitivity of the Abbott assay dropped to 77.2% but remained at 100% for the Roche assay. A redefined Abbott threshold of 0.64 increased the sensitivity to 90% giving results similar to Roche and TBS assaysConclusionThis study demonstrated Abbott assay had a lower sensitivity in comparison to TBS and Roche. Furthermore, TBS can be implemented as a viable alternative for SARS-CoV-2 serology testing where high-throughput assays are not available on site.Trial registration number and date of registrationNot applicable.Trial registration number, date of registration followed by “retrospectively registered”Not applicable.AbstractSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serology testing is key for assessing seroprevalence and antibody response post-vaccination in immunocompromised patients. Here we performed a comparison between two high-throughput nucleocapsid assays (Abbott SARS-CoV-2 IgG and Roche Elecsys Anti-SARS-CoV-2) and The Binding Site (TBS) anti-Spike IgG/A/M-SARS-CoV-2 ELISA kit. 236 samples were collected across 2 sites, Portsmouth Hospital University NHS Trust (PHU) and The Dudley Group NHS Trust. We derived concordance, agreement and assay performance as well as using receiver operating characteristic (ROC) curves to redefine the assay threshold of the Abbott assay. Result concordance between the Abbott and TBS was 66%. Discrepant samples were analysed using the Roche assay which showed 100% agreement with the TBS assay. In samples analysed >58 days post-PCR, the sensitivity of Abbott and Roche was 100%. In samples analysed >100 days post-PCR the sensitivity of the Abbott assay dropped to 77.2% but remained at 100% for the Roche assay. A redefined Abbott threshold of 0.64 increased the sensitivity to 90% giving results similar to the Roche and TBS assays. In conclusion, this study demonstrated Abbott assay had a lower sensitivity in comparison to TBS and Roche. This study established TBS can be implemented as a viable alternative for SARS-CoV-2 serology testing where high-throughput assays are not available on site. Furthermore, anti-spike assays, such as TBS, could be used to monitor vaccination responses to deduce SARS-CoV-2 population-immunity. Further optimisation studies are required to evaluate the performance characteristics of these assays which could facilitate widescale sero-epidemiological surveillance.

Background The novel coronavirus SARS-CoV2 that causes COVID-19 has resulted in the death of more than 2.5 million people, but no cure exists. Although passive immunization with COVID-19 convalescent plasma (CCP) provides a safe and viable therapeutic option, the selection of optimal units for therapy in a timely fashion remains a barrier. Study design and methods Since virus neutralization is a necessary characteristic of plasma that can benefit recipients, the neutralizing titers of plasma samples were measured using a retroviral-pseudotype assay. Binding antibody titers to the spike (S) protein were also determined by a clinically available serological assay (Ortho-Vitros total IG), and an in-house ELISA. The results of these assays were compared to a measurement of antibodies directed to the receptor binding domain (RBD) of the SARS-CoV2 S protein (Promega Lumit Dx). Results All measures of antibodies were highly variable, but correlated, to different degrees, with each other. However, the anti-RBD antibodies correlated with viral neutralizing titers to a greater extent than the other antibody assays. Discussion Our observations support the use of an anti-RBD assay such as the Lumit Dx assay, as an optimal predictor of the neutralization capability of CCP.

Highlights • Elderly patients in nursing homes often present an atypical course of COVID-19 disease. • Fever is one of the pivotal signs in COVID-19 patients. • The prevalence of fever was extremely low in our population of nursing home SARS-CoV-2-positive patients. • This finding must be considered in the diagnostic workup of suspected COVID-19 patients., Objectives Residents in nursing homes represent a frail population of patients, and SARS-CoV-2 infection can spread easily in this setting. Despite a frequent severe evolution of the disease, these patients often present an atypical course with mild initial symptoms. Thus, the aim of this study was to assess the occurrence of fever in elderly SARS-CoV-2 positive patients residing in nursing homes. Methods 231 elderly patients from three nursing homes of Pavia and its Province were enrolled in April-May 2020. Diagnosis of SARS-CoV-2 infection was performed using real-time RT-PCR on nasopharyngeal swab and/or serological assay (LIAISON® SARS-CoV-2 S1/S2 IgG). Positive patients were defined by positivity at nasopharyngeal swab and/or at serology. Results 170 patients (74%) were SARS-CoV-2-positive, 61 subjects (26%) resulted negative at both tests. Fever (T > 37,5 °C) was observed only in four patients (1,7%), three in the SARS-CoV-2-positive group (1,7%) and one in the SARS-CoV-2-negative one (1,6%). Conclusions The prevalence of fever was extremely low in our population of nursing home SARS-CoV-2-positive patients. Thus, this finding must be taken into consideration when screening patients without fever in nursing homes.

The implementation of strategies to mitigate possible cases of COVID-19 were addressed at the University of Alicante for the safe reopening of the 2020/2021 academic year. To discover the prevalence of immunity against SARS-CoV-2, a study was designed using a rapid immunoassay test (carried out between 6 and 22 July 2020), and in addition a cross-sectional survey was conducted on risk factors, symptoms, predisposition for becoming vaccinated, and sources of information about COVID-19. A random sample, stratified by students, faculty, and administrative staff, was selected. The seroprevalence found was 2.64% (39/1479, 95% CI 1.8–3.4), and the adjusted seroprevalence was 2.89% (95% CI 2.1–3.7). The average age of the students was 23.2 years old, and 47.6 years old for staff. In relation to COVID-19, the following was found: 17.7% pauci-symptomatic, 1.3% symptomatic, 5.5% contact with cases, 4.9% confined, and 0.3% PCR positive. More than 90% complied with preventive measures. The proportion willing to receive the COVID-19 vaccine was 91%. Their sources of information were the Internet (74%) and television (70.1%). They requested that the university offer information (45.1%), training (27%), and provide Personal Protective Equipment (PPE) (26.3%). Lastly, 87.9% would repeat the test. A plan was established that included the follow-up of cases and contacts, random sample testing, training courses, bimodal teaching, a specific website, and the distribution of PPE.

Tests for visceral leishmaniasis (VL) are not uniformly effective for all endemic regions. In a serological assay, a novel antigen, otubain cysteine peptidase, compared with rK39, showed comparable sensitivity with Indian VL serum samples and prominently increased sensitivity with Brazilian samples, as well as improved monitoring of the treatment response.

Whipple’s disease (WD) is a rare infection due to Tropheryma whipplei. Following in-vitro cultivation of T. whipplei, an indirect-immunofluorescence serological assay (IFA) was developed. We tested the hypothesis that this assay could be used to either identify WD patients, or rule out WD, in patients in whom the diagnosis is being considered, based on the antibody titers of their IgM and IgG antibody responses. In this small study fourteen WD patients and 22 healthy volunteers’ sera were obtained from across Australia. All specimens were coded and de-identified before testing. A patient with an IgG antibody titer of ≤1:16 may have WD [sensitivity 57% (8/14) and specificity close to 100% (22/22)]. High IgM antibody titers (≥1:256) were more common in WD patients [sensitivity 50% (7/14) and specificity 86% (19/22)] than in controls. The area under Receiver-Operator-Characteristic curve for IgG in the IFA assay was 0.84 (95% CI 0.69-1.00). At an IgG antibody titer of ≤1:16 the Youden’s index was 0.57. WD patients’ under-produce IgG antibody to T.whipplei but are more likely to over-produce IgM antibodies. This screening IFA serological assay may be clinically useful in detecting those with a possible diagnosis of WD. Patients with an IgG antibody titer of ≤1:16 and an IgM antibody titer of ≥1:256 may have WD and should proceed to a tissue biopsy and PCR for confirmation. Further validation of this assay, by increasing the sample size, by testing it in patients with non-WD disease and trialing in other countries should be undertaken.

The prognosis of COVID-19 (coronavirus disease 2019) is usually poor when it occurs in aged adults or in patients with chronic diseases, which brought a great challenge to clinical practice. Furthermore, widespread depression, anxiety, and panic related to SARS-CoV-2 (severe acute respiratory syndrome-coronavirus 2) infection affected treatment compliance and recovery. Here we report the successful treatment of a 57-year-old male with severe COVID-19, schizophrenia, hypertension, and type 2 diabetes. The patient's negative emotions (such as tension, panic, and anxiety), particularly his aggression and paranoia, seriously hindered treatment, leading to a deteriorating condition. Psychological counseling and supportive psychotherapy were given but the effect was weak. To improve adherence, risperidone and quetiapine fumarate were replaced by olanzapine for anti-schizophrenic treatment to reduce insomnia and anxiety side effects, associated with sedative-hypnotic drugs as well as psychological counseling. The treatment compliance of the patient improved significantly. The patient's serum alanine aminotransferase increased abnormally in the late stage of hospitalization, suggesting potential liver damage after complex medication strategies. We also monitored the changes of lymphocyte subsets and retrospectively analyzed the virus-specific antibody response. The results suggested that dynamic monitoring of lymphocyte subsets and virus-specific antibody response could facilitate disease progression evaluation and timely treatment plan adjustments. An effective psychotropic drug intervention associated with psychological counselling and psychotherapy are essential for the successful adherence, treatment, and rehabilitation of psychiatric disorders in COVID-19 patients.

SARS-CoV-2 virus is responsible for the current worldwide coronavirus disease 2019 (COVID-19) pandemic, infecting millions of people and causing hundreds of thousands of deaths. Understanding the antibody response to SARS-CoV-2 is crucial for the development of vaccines, therapeutics and public health interventions. However, lack of consistency in methods used to monitor antibody response to SARS-CoV-2 leaves some uncertainty in our fine understanding of the human antibody response mounted following SARS-CoV-2 infection. We developed a peptide-based enzyme-linked immunosorbent assay (ELISA) by selecting 7 synthetic peptides from the spike, membrane, and nucleocapsid protein sequences of SARS-CoV-2, which effectively detects the antibody response mounted by all COVID-19 convalescent tested. Strikingly, the assay shows a profound difference in antibody response among individual subjects, which may have a significant impact on disease severity. Together, our results define an efficient and specific serological assay to consistently measure the antibody response following SARS-CoV-2 infection, as well as help the design of vaccine and therapeuticals for prevention and treatment of COVID-19.

Spike (S)-and nucleocapsid (N)-specific serological assay responses were determined before and/or after first dose SARS-CoV-2 vaccination in 22 individuals. S-specific assays quantified antibodies after vaccination with significant higher levels in participants with a previous infection. Be cautious combining N-/S-specific assay results, potentially differentiating post-infection/vaccination immunization as assay-specific N-anti-body waning was observed. (c) 2021 Elsevier Inc. All rights reserved.

Highlights • Deep learning technology applied to diagnosis of Acute Promyelocytic Leukemia (APL). • Convolutional neural networks (Mask R-CNN) may diagnose APL in bone marrow smear images with a high precision. • Data augmentation and pre-trained approach improves diagnostic accuracy., Background Serological severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody assays differ in the target antigen specificity, e.g. of antibodies directed against the viral spike or the nucleocapsid protein, and in the spectrum of detected immunoglobulins. The aim of the study was to evaluate the performance of two different routinely used immunoassays in hospitalized and outpatient COVID-19 cases. Methods The test characteristics of commercially available spike1 protein-based serological assays (Euroimmun, EI-assays), determining IgA or IgG and nucleocapsid-based assays (Virotech, VT-assays) determining IgA, IgM or IgG were compared in 139 controls and 116 hospitalized and outpatient COVID-19 cases. Results Hospitalized COVID-19 patients (n = 51; 115 samples) showed significantly higher concentrations of antibodies against SARS-CoV-2 and differed from outpatient cases (n = 65) by higher age, higher disease severity scores and earlier follow up blood sampling. Sensitivity of the two IgG assays was comparable in hospitalized patients tested ≥ 14 days (EI-assay: 88%, CI95% 67.6–99.9; VT-assay: 96%, CI95% 77.7–99.8). In outpatient COVID-19 cases sensitivity was significantly lower in the VT-assay (86.2%, CI95% 74.8–93.1) compared with the EI-assay (98.5%, CI95% 90.6–99.9). Assays for IgA and IgM demonstrated a lack of specificity or sensitivity. Conclusions Our results indicate that SARS-CoV-2 serological assays may need to be optimized to produce reliable results in outpatient COVID-19 cases who are low or even asymptomatic. Assays for IgA and IgM have limited diagnostic performance and do not prove an additional value for population-based screening approaches.

Background: Serological tests are crucial tools for assessments of SARS-CoV-2 exposure, infection and potential immunity. Their appropriate use and interpretation require accurate assay performance data. Method: We conducted an evaluation of 10 lateral flow assays (LFAs) and two ELISAs to detect anti-SARS-CoV-2 antibodies. The specimen set comprised 128 plasma or serum samples from 79 symptomatic SARS-CoV-2 RT-PCR-positive individuals; 108 pre-COVID-19 negative controls; and 52 recent samples from individuals who underwent respiratory viral testing but were not diagnosed with Coronavirus Disease 2019 (COVID-19). Samples were blinded and LFA results were interpreted by two independent readers, using a standardized intensity scoring system. Results: Among specimens from SARS-CoV-2 RT-PCR-positive individuals, the percent seropositive increased with time interval, peaking at 81.8–100.0% in samples taken >20 days after symptom onset. Test specificity ranged from 84.3–100.0% in pre-COVID-19 specimens. Specificity was higher when weak LFA bands were considered negative, but this decreased sensitivity. IgM detection was more variable than IgG, and detection was highest when IgM and IgG results were combined. Agreement between ELISAs and LFAs ranged from 75.7–94.8%. No consistent cross-reactivity was observed. Conclusion: Our evaluation showed heterogeneous assay performance. Reader training is key to reliable LFA performance, and can be tailored for survey goals. Informed use of serology will require evaluations covering the full spectrum of SARS-CoV-2 infections, from asymptomatic and mild infection to severe disease, and later convalescence. Well-designed studies to elucidate the mechanisms and serological correlates of protective immunity will be crucial to guide rational clinical and public health policies.

Coronavirus Disease 2019 (COVID-19) is a global pandemic caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). While detection of SARS-CoV-2 by polymerase chain reaction with reverse transcription (RT-PCR) is currently used to diagnose acute COVID-19 infection, serological assays are needed to study the humoral immune response to SARS-CoV-2. SARS-CoV-2 IgG/A/M antibodies against SARS-CoV-2 spike (S) protein and its receptor-binding domain (RBD) were characterized using an enzyme-linked immunosorbent assay (ELISA) and assessed for their ability to neutralize live SARS-CoV-2 virus in recovered subjects who were RT-PCR-positive (n=153), RT-PCR-negative (n=55), and control samples collected pre-COVID-19 (n=520). Anti-SARS-CoV-2 antibodies were detected in 90.9% of resolved subjects up to 180 days post-symptom onset. Anti-S protein and anti-RBD IgG titers correlated (r= 0.5157 and r = 0.6010, respectively) with viral neutralization. Of the RT-PCR-positive subjects, 22 (14.3%) did not have anti-SARS-CoV-2 antibodies; and of those, 17 had RT-PCR cycle threshold (Ct) values >27, raising the possibility that these indeterminate results are from individuals who were not infected, or had mild infection that failed to elicit an antibody response. This study highlights the importance of serological surveys to determine population-level immunity based on infection numbers as determined by RT-PCR.

A critical point in the management of the SARS-CoV-2 pandemic is the need to promptly identify the greatest number of infected people and to implement strict public health measures. In this study, the performance of a rapid serological test in a clinical setting was evaluated. Samples from 819 consecutive patients (with or without respiratory symptoms) admitted to a large Emergency Department were tested between 23 March and 21 April 2020. Patient samples were tested in a real-time PCR assay and a serological assay. In total, 148/819 patients (18.1%) tested positive for SARS-CoV-2 by real-time PCR. The serological test revealed that 70/819 patients (8.5%) had anti-SARS-CoV-2 IgM and/or IgG. The prevalence of anti-SARS-CoV-2 antibodies was significantly higher in patients with respiratory symptoms lasting for &gt, 7 days than in those with respiratory symptoms lasting for 0&ndash, 7 days (p &lt, 0.001). The serological assay had an overall sensitivity of 35.1% and an overall specificity of 97.3%. A high negative predictive value (96.7%) was reported for patients without respiratory symptoms. The results confirm that rapid serological assays alone are not sufficient for diagnosis of SARS-CoV-2 infection but can be incorporated into large-scale screening programs during periods in which the virus circulation is low.

The capacity to accurately diagnosis COVID-19 is essential for effective public health measures to manage the ongoing global pandemic, yet no presently available diagnostic technologies or clinical protocols can achieve full positive predictive value (PPV) and negative predictive value (NPV) performance. Two factors prevent accurate diagnosis: the failure of sampling methods (e.g., 40% false negatives from PCR testing of nasopharyngeal swabs) and sampling-time-dependent failures reflecting individual humoral responses of patients (e.g., serological testing outside of the sero-positive stage). Here, we report development of a diagnostic protocol that achieves full PPV and NPV based on a cohort of 500 confirmed COVID-19 cases, and present several discoveries about the sero-conversion dynamics throughout the disease course of COVID-19. The fundamental enabling technology for our study and diagnostic protocol—termed SANE, for Symptom (dpo)-Antibody-Nucleic acid-Epidemiological history—is our development of a peptide-protein hybrid microarray (PPHM) for COVID-19. The peptides comprising PPHMcovid-19 were selected based on clinical sample data, and give our technology the unique capacity to monitor a patient’s humoral response throughout the disease course. Among other assay-development related and clinically relevant findings, our use of PPHMcovid-19 revealed that 5% of COVID-19 patients are from an “early sero-reversion” subpopulation, thus explaining many of the mis-diagnoses we found in our comparative testing using PCR, CLIA, and PPHMcovid-19. Accordingly, the full SANE protocol incorporates orthogonal technologies to account for these patient variations, and successfully overcomes both the sampling method and sampling time limitations that have previously prevented doctors from achieving unambiguous, accurate diagnosis of COVID-19.

Nucleic acid real-time PCR test has become the main diagnostic tool for SARS‐CoV‐2 infection, and there are also drawbacks to these real-time PCR test kits. Additionally, it has reported high false-negative rates. A reliable and rapid test method is urgently required to briskly detect antibody response in a large number of infected patients and ensure prompt care for patients. Therefore, we report here a Luminex bead based multiplexed immunoassay to serologically diagnose the SARS-CoV2 infection and detect IgM and IgG response in COVID-19 patients. The technology can provide sensitive and specific detection using a low amount of serum samples in high-throughput screening platforms.

SARS-CoV-2 serological tests are a subject of intense interest and have the potential to significantly enhance the diagnostic capability of healthcare services in the current pandemic. However, as with all novel assays, significant validation is required to understand the clinical relevance of results. We present the first study to assess clinician interpretation of SARS-CoV-2 serology scenarios. We identify common key assumptions regarding patient infectivity and protection that are not currently supported by the SARS-CoV-2 evidence base. In this rapidly developing field, we therefore strongly recommend serological assay results are accompanied by clear interpretive support from laboratory and infectious diseases specialists.

BackgroundRT-PCR test for identification of viral nucleic acid is the current standard diagnostic method for the diagnosis of COVID-19 disease but technical reasons limit the utilization of this assay onlarge scalescreenings.MethodWe verified in a consecutive series of 191 symptomatic patients the clinical information that new rapid serological colorimetric test qualitatively analyzing IgM/IgG expression can provide with respect to standard assay and with respect to clinical outcome of patients.ResultsRapid serological test showed a sensitivity of 30% and a specificity of 89% with respect to the standard assay but, interestingly, these performances improve after 8 days of symptoms appearance. After 10 days of symptoms the predictive value of rapid serological test is higher than that of standardassay. When the behaviour of the two immunoglobulins was evaluated with respect to time length of symptoms appaerance, no significant difference in immunoglobulins behaviour was shown.ConclusionsThe rapid serological test analyzed in the present study is candidate to provide information on immunoreaction of the subject to COVID-19 exposure.

BackgroundThe outbreak of the recently emerged novel corona virus disease 2019 (COVID-19) poses a challenge for public health laboratories. We aimed to evaluate the diagnostic value of serological assay for SARS-CoV-2.MethodsA newly-developed ELISA assay for IgM and IgG antibodies against N protein of SARS-CoV-2 were used to screen the serums of 238 admitted hospital patients with confirmed or suspected SARS-CoV-2 infection from February 6 to February 14, 2020. SARS-CoV-2 RNA was detected by real time RT-PCR on pharyngeal swab specimens.FindingsOf the 238 patients, 194 (81.5%) were detected to be antibody (IgM and/or IgG) positive, which was significantly higher than the positive rate of viral RNA (64.3%). There was no difference in the positive rate of antibody between the confirmed patients (83.0%, 127/153) and the suspected patients (78.8%, 67/85) whose nucleic acid tests were negative. After the patients were defined to the different stages of disease based on the day when the test samples were collected, the analysis results showed that the antibody positive rates were very low in the first five days after initial onset of symptoms, and then rapidly increased as the disease progressed. After 10 days, the antibody positive rates jumped to above 80% from less than 50%. On the contrary, the positive rates of viral RNA kept above 60% in the first 11 days after initial onset of symptoms, and then rapidly decreased. In addition, half of the suspected patients with symptoms for 6-10 days were detected to be antibody positive.InterpretationThe suspected patients were most likely infected by SARS-CoV-2. Before the 11th day after initial onset of symptoms, nucleic acid test is important for confirmation of viral infection. The combination of serological assay can greatly improve the diagnostic efficacy. After that, the diagnosis for viral infection should be majorly dependent on serological assay.

INTRODUCTION: Human herpesvirus (HHV)-7 establishes a latent infection during the lifetime of the host and can reactivate after the primary infection, leading to lytic replication in immunosuppressed patients. METHODS: This study aimed to develop an enzyme-linked immunosorbent assay (ELISA) to identify HHV-7 serum antibodies and compare its performance with that of an indirect immunofluorescence assay (IFA). RESULTS: Serum samples (n=102) were tested by IgG-IFA and by ELISA. IFA and ELISA showed IgG-positive results in 77 and 73 samples, respectively. Qualitative concordance of 96% was demonstrated between the two techniques. CONCLUSIONS: ELISA may be useful to diagnose HHV-7 infection.

Over the last decade, significant advances have been made in the development of biomarkers for the detection of Mycobacterium leprae infection. Nevertheless, given the wide spectrum of clinical manifestations of leprosy, and the variability in the individual response from distinct leprosy-endemic areas, the proposition of a serological assay for the early diagnosis still remains a challenge. Thus, at present, an effective medical intervention to avoid leprosy-provoked disabilities, exclusively depends on efficient anamnesis and clinical assessment, by appropriately trained and qualified professionals. The efforts of the scientific community to develop engineered antigen-based assays, for serological diagnosis of leprosy are covered. Finally, the importance of awareness in demystifying the disease, and encouraging early reporting, is appointed as the first step to avoid disabilities, and control the transmission of leprosy.

Introduction. The gold-standard method for diagnosis of the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 or COVID-19) foresees the examination of respiratory tract swabs by real-time reverse-transcription polymerase chain reaction (rRT-PCR). Another group of diagnostic tests, developed to overcome the limitations of RT-PCR, includes the serological assays, which have the purpose of detecting the antibody response to SARS-CoV-2 infection (IgM and IgG titers). The aim of this review was to establish the diagnostic capability of the existing serological tests in the detection of SARS-CoV-2 infection. Materials and Methods. Electronic research was conducted in PubMed, Scopus, Science Direct and Cochrane Library, and only 10 articles, testing 10 different types of serological assays, met the inclusion criteria and were consequently submitted to quality assessment and data extraction. Quantitative data about the sensitivity, specificity, positive/negative predictive value and IgM/IgG titer provided by each antibody test were reported in our review. Results. Almost all the serological tests used in the included items were recorded to ensure high sensitivity and specificity, identifying the presence of IgM and IgG antibodies against SARS-CoV-2 in patients with certain COVID-19 diagnosis (confirmed by RT-PCR) and in participants with suspected infection (SARS-CoV-2 clinical diagnosis and/or RT-PCR negative subjects). Conclusion. Serological tests may represent reliable diagnostic tools in the detection of SARS-CoV-2 infection, and they could be implemented complementary to real-time RT-PCR.

Seeds are the basic input for crop production. Infected or contaminated seed is the primary source of inoculum for a large number of destructive diseases of important food, fodder and fibre crops. In this context, seed health tests have become a major component towards sustainable crop production and crop productivity. Apart from seed health testing, the seed certification for a crop comprises legal norms to be qualified for ensuring genetic identity, physical purity, germinability and freedom from seed-transmitted pathogens and weeds. Mainly different types of conventional methods followed by molecular methods are employed for seed health testing. Conventional methods include visual inspection of seeds, washing test, seed soak method and incubation methods, while serological assay and nucleic acid-based techniques are the most accurate and least time-consuming which comes under molecular method of seed health testing. The conventional methods are mostly based on interpretation of visual symptoms, culturing and laboratory identification. Thus, it is almost difficult to interpret results with hidden symptoms. However, among all techniques available, nucleic acid-based techniques are the most accurate and least time-consuming.

Middle East respiratory syndrome coronavirus (MERS-CoV) is the etiological agent of MERS, a severe respiratory disease first reported in the Middle East in 2012. Serological assays are used to diagnose MERS-CoV infection and to screen for serum antibodies in seroepidemiological studies. The conventional enzyme-linked immunosorbent assay (ELISA) is the preferred tool for detecting serum antibodies specific for pathogens; however, the utility of conventional ELISA with respect to detection of MERS-CoV antibodies is limited due to the number of false-positives caused by cross-reactivity of serum antibodies with antigens that are conserved among coronaviruses. The competitive ELISA (cELISA) uses a pathogen-specific monoclonal antibody (MAb) that competes with serum antibodies for binding to an antigen; therefore, it is used widely for serological surveillance of many pathogens. In this chapter, I describe detection of serum antibodies using cELISA based on MAbs specific for MERS-CoV.

Hepatitis C virus (HCV) infection is a blood borne and transfusion-transmitted infection (TTI). It has emerged as one of the major health challenges worldwide. In India, around 12-18 million peoples are infected with HCV, but in terms of prevalence percentage, its looks moderate due to large population. The burden of the HCV infection increases due to lack of foolproof screening of blood and blood products before transfusion. The qualified screening and quantification of HCV play an important role in diagnosis and treatment of HCV-related diseases. If identified early, HCV infection can be managed and treated by recently available antiviral therapies with fewer side effects. However, its identification at chronic phase makes its treatment very challenging and sometimes ineffective. The drugs therapy for HCV infection treatment is also dependent on its genotype. Different genotypes of HCV differ from each other at genomic level. The RNA viruses (such as HCV) are evolving perpetually due to interaction and integration among people from different regions and countries which lead to varying therapeutic response in HCV-infected patients in different geographical regions. Therefore, proper diagnosis for infecting virus and then exact determination of genotype become important for targeted treatment. This review summarizes the general information on HCV, and methods used for its diagnosis and genotyping.

A novel clinical assay for the detection and quantitation of antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was adapted from an in-house, research-based enzyme-linked immunosorbent assay (ELISA). Development and validation were performed under regulatory guidelines, and the test obtained emergency use authorization (EUA) from the New York State Department of Health (NYSDOH) and the Food and Drug Administration (FDA). The Mount Sinai coronavirus disease 2019 (COVID-19) antibody assay is an orthogonal, quantitative direct ELISA test which detects antibodies reactive to the receptor binding domain (RBD) and the spike protein of the novel SARS-CoV-2. The assay is performed on 96-well plates coated with either SARS-CoV-2 recombinant RBD or spike proteins. The test is divided into two stages, a qualitative screening assay against RBD and a quantitative assay against the full-length spike protein. The test uses pooled high titer serum as a reference standard. Negative pre-COVID-19 and positive post-COVID-19, PCR-confirmed specimens were incorporated in each ELISA test run, and the assays were performed independently at two different locations. The Mount Sinai COVID-19 serology performed with high sensitivity and specificity, 92.5% (95% CI: 0.785–0.980) and 100% (CI: 0.939–1.000) respectively. Between-run precision was assessed with a single run repeated over 22 days; and within-run precision was assessed with 10 replicates per day over 22 days. Both were within reported acceptance criteria (CV ≤ 20%). This population-based study reveals the applicability and reliability of this novel orthogonal COVID-19 serology test for the detection and quantitation of antibodies against SARS-CoV-2, allowing a broad set of clinical applications, including the broad evaluation of SARS-CoV-2 seroprevalence and antibody profiling in different population subsets., Coronavirus disease 2019; Severe acute respiratory syndrome coronavirus-2 (SARSCoV-2); Antibody tests; Diagnosis of COVID-19; ELISA; IgG antibody assay.

Serology tests are extremely useful for assessing whether a person has been infected with a pathogen. Since the onset of the COVID-19 pandemic, measurement of anti-SARS-CoV-2-specific antibodies has been considered an essential tool in identifying seropositive individuals and thereby understanding the extent of transmission in communities. The Luminex system is a bead-based technology that has the capacity to assess multiple antigens simultaneously using very low sample volumes and is ideal for high-throughput studies. We have adapted this technology to develop a COVID-19 multi-antigen serological assay. This protocol described here carefully outlines recommended steps to optimize and establish this method for COVID-19-specific antibody measurement in plasma and in saliva. However, the protocol can easily be customized and thus the assay is broadly applicable to measure antibodies to other pathogens.

Two plasmid gene protein (Pgp3)-based serological assays, the Pgp3-ELISA and multiplex bead assay (Pgp3-MBA), were compared and used to estimate seropositivity of Chlamydia trachomatis (CT) among females 14 to 39 years old participating in the National Health and Nutrition Examination Survey between 2013–2016. Of the 2,201 specimens tested, 502 (29.5%, 95% CI 27.6–31.5) were positive using Pgp3-ELISA and 624 (28.4%, 95% CI 26.5–30.3) were positive using Pgp3-MBA. The overall agreement between the assays was 87.7%. Corresponding nucleic acid amplification test (NAAT) results were available for 1,725 specimens (from women 18–39 years old); of these, 42 (2.4%, 95% CI 1.8–3.3) were CT NAAT-positive. Most of the CT NAAT-positive specimens had corresponding positive serological assay results; 33 (78.6%, 95% CI 62.8–89.2) were Pgp3-ELISA-positive and 36 (85.7%, 95% CI 70.8–94.1) were Pgp3-MBA-positive. Although Pgp3-ELISA and Pgp3-MBA demonstrated equivalent performance in this study, an advantage of the Pgp3-MBA over Pgp3-ELISA is that it is well suited for high sample throughput applications.

Tobacco streak virus (TSV), inciting cotton necrosis, exhibits multifarious symptoms. Common types of symptoms include, purplish brown, necrotic lesions in the leaves, squares, and petioles. Telangana (India) had the highest incidence of TSV (51.11 PDI - hybrid RCH659), among the surveyed locations including, Tamil Nadu, Andhra Pradesh, Telangana and Maharashtra states of India. Environmental factors greatly influenced the establishment of TSV in cotton. Minimum temperature (22.81 °C), relative humidity (81.42%), and leaf wetness (23.94 h) favoured maximum TSV incidence with a mean PDI of 30.68 at Annur, (Tamil Nadu, India). Serological assay through DAC-ELISA confirmed the presence of TSV in cotton samples expressing necrosis symptoms. Bioassay revealed that Chenopodium amaranticolor and Chenopodium quinoa are excellent indicator host plants with high virus titres. Further, molecular characterization revealed the conserved nature of the coat protein gene, among the TSV isolates infecting cotton in four different states (Tamil Nadu, Andhra Pradesh, Telangana, and Maharashtra).