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Objectives/hypothesis The accurate diagnostic assessment of clinically relevant human papillomavirus (HPV) infections in patients with head and neck squamous cell carcinoma represents an urgent unmet medical need. The aim of this study was to determine feasibility, accuracy, and clinical significance of HPV16/18 E6 oncoprotein detection on cytological specimens from oropharyngeal squamous cell carcinoma (OPSCC) and neck lymph node metastasis of SCC from unknown primary tumor (CUP) via a protein immunochromatographic assay. Study design Cross-sectional study. Methods Cytological specimens from primary tumor and neck metastases were collected from 34 patients with OPSCC or CUP and applied to a lateral flow format test that detects HPV16 and HPV18 E6 oncoproteins. E6 oncoprotein positivity or negativity in these specimens was compared to the specimens' "HPV-driven" reference status, defined by presence of HPV-DNA in combination with p16INK4a overexpression and/or HPV E6 seropositivity. Results Eighteen of 29 OPSCC (62%) and three of five CUP (60%) were HPV-driven according to our reference method. The E6 oncoprotein lateral flow test had a sensitivity of 94% (95% CI: 70%-100%) and a specificity of 100% (95% CI: 66%-100%) on primary tumor, and a sensitivity of 88% (95% CI: 64%-99%) and a specificity of 100% (95% CI: 74%-100%) on neck metastases. Test agreement between the E6 lateral flow test and the clinical reference method, HPV-DNA plus p16INK4a was excellent, both for primary lesion and neck metastases. Conclusions We found the detection of HPV16/18 E6 oncoproteins to be a feasible, highly reliable, and low-invasive method to assess "HPV-driven" status in OPSCC and CUP. Level of evidence II Laryngoscope, 131:1042-1048, 2021.

In this work,we presented the development of cost-effective dual sensitivity enhancement in gold nanoparticle-based lateral flow test strip for detection of carcinoembryonic antigen. On the one hand, we employed protein G as a host matrix for oriented immobilization of antibodies within the nitrocellulose membrane. On the other hand, we utilized gold enhancement approach to visualize the final signals effectively. Primary examinations revealed that the smaller sized nanoparticles have greater signal enhancement compared to bigger ones. So, mono-dispersed gold nanoparticles with average diameters of 11.40 ± 1.40 nm were utilized as tags. The measurement of fluorescent intensity of FITC-tagged secondary antibody attached to the polyclonal antibody, in the presence/absence of protein G as a host matrix on microplate wells, showed the successful oriented immobilization of antibodies via the host matrix. The FESEM images confirmed the attachment and growth of nanoparticles within the porous nitrocellulose membrane, after gold enhancement. Finally, under the optimized conditions, the developed strip could quantify the standard values of target within 2-50 ng/mL range with a limit of detection of 0.35 ng/mL. This strategy enabled the reduction of antibody consumption from a conventional amount of 0.6 μg/strip down to 0.012 μg/strip. The serum samples containing carcinoembryonic antigen were also successfully analyzed by the developed strip with a visual detection limit of 10 ng/mL, which confirms favorable characteristics of the developed test strip for point-of-care applications.

Detection of pathogenic bacteria in complex biological matrices remains a major challenge. Herein, we report the selection and optimization of a new DNAzyme for Staphylococcus aureus (SA) and the use of the DNAzyme to develop a simple lateral flow device (LFD) for detection of SA in nasal mucus. The DNAzyme was generated by in vitro selection using a crude extra/intracellular mixture derived from SA, which could be used directly for simple solution or paper-based fluorescence assays for SA. The DNAzyme was further modified to produce a DNA cleavage fragment that acted as a bridging element to bind DNA-modified gold nanoparticles to the test line of a LFD, producing a simple colorimetric dipstick test. The LFD was evaluated with nasal mucus samples spiked with SA, and demonstrated that SA detection was possible in minutes with minimal sample processing.

Papers based biosensors such as lateral flow test strips and paper-based microfluidic devices are inex- pensive, rapid, flexible, and easy-to-use analytical tools for point-of-care diagnosis. An apparent trend in their de- tection is to interpret sensing results from qualitative as- sessment to quantitative determination. Electrochemical (EC) detection plays an important role in quantifying test results. This review focuses on paper-based biosensors with EC detection. The first part provides detailed exam- ples in lateral flow test strips while the second part gives an overview of paper microfluidics. The outlook and rec- ommendation of future directions of papers based EC biosensors are discussed in the end.

Objective To evaluate a point-of-care anticoagulant rodenticide lateral flow analyzer for the detection of various rodenticide compounds. Design Prospective, laboratory study. Setting University teaching hospital. Animals The study utilized a serum sample from one healthy canine donor. Samples were centrifuged and serum samples were aliquoted and either used within 4 hours or frozen at −70°C for further quantitative analysis. Interventions Samples were spiked with clinically relevant concentrations of 1 of 6 rodenticide compounds (warfarin, pindone, chlorphacinone, brodifacoum, bromethalin, and its metabolite desmethylbromethalin). Seventy-five microliters of spiked serum (or unaltered serum) was introduced into the lateral flow test. Measurements and Main Results Three readers who were blinded to the sample preparation interpreted the lateral flow test as either positive or negative for the presence of anticoagulant rodenticide. All readers were in agreement for the results of each serum sample. The point-of-care test kit was able to detect a single anticoagulant rodenticide (warfarin) at concentrations below the manufacturer's recommended limit of detection, but was unable to detect any other anticoagulant rodenticide. Conclusions The results of this test and therapeutic interventions must be considered in light of history, physical examination, and other clinical data. Based on results from this study, the test kit only detects warfarin and not other more common second-generation anticoagulant rodenticides.

BACKGROUND International guidelines recommend allergen avoidance for asthma management, but do not include making assessments of allergen exposure. Mite allergen exposure cannot be assumed, especially in geographical regions where climatic conditions vary. OBJECTIVE To develop a rapid test that would enable consumers to detect mite allergen in the home. METHODS A lateral flow test using gold labelled antibody for mite group 2 allergen was developed as part of a detection kit incorporating the MITEST dust sampling device. Dust samples were assayed by ELISA for group 1 and group 2 allergens and by using the rapid test. The tests were compared as indices of mite allergen exposure. RESULTS There was a good correlation between group 1 and group 2 levels by ELISA (n = 349, r = 0.60, P 1 microg/m2 group 2 allergen, whereas most low samples contained < 1 microg/m2 (50/64, 78%). Differences between mean group 2 levels of samples that scored low (0.28 microg/m2), medium (1.68 microg/m2) or high (3.18 microg/m2) on the test were highly significant (P 0.007 to < 0.001). CONCLUSIONS A simple rapid test has been developed that detects mite allergen in the home within 10 min. The mite screening test should educate consumers about allergen exposure and encourage compliance with allergen-avoidance procedures. This technology has applications for the detection of other common environmental allergens.

Streptococcal tonsillitis, streptococcal pharyngitis,or streptococcal sore throat (known commonly as strep throat) is a type of pharyngitis caused by a group A streptococcal infection. It affects t...

Summary Current market conditions and food regulations make it necessary for international and domestic participants in the agrifood industry to structure supply chains that control the content of genetically modified (GM) material in their products. Tests to detect and/or quantify GM components represent an important tool in maintaining such supply systems. This study assesses the field performance of kits that employ lateral flow immuno-technology to detect soybeans GM to be resistant to the herbicide glyphosate. Operators at 23 grain-handling facilities were paid to conduct analyses on a series of blinded samples containing defined proportions of conventional and transgenic soybeans. The observed rate of false positives was 6.7% in an experiment in which the highest level of GM material was 1% and 22.3% in a second experiment in which the highest level of GM material was 10%. This difference may be attributed to increased risk of cross-contamination with the higher level of transgenic material used in the second study. Samples containing 0.01% GM material were reported as genetically modified 6.70% of the time, while samples containing 0.1, 0.5 and 1% GM material were classified as genetically modified 29.5, 67.7 and 68.2% of the time, respectively. Thus, the frequencies of false negatives were 93.3, 70.5, 33.3 and 31.8% for samples containing 0.01, 0.1, 0.5 and 1.0% GM material. Samples containing 10% GM material were correctly reported as genetically modified in all cases. These results lead to the conclusion that the kit under study is useful in screening for lots of soybeans that contain high levels of GM material, but that, as a field tool, it is not effective in monitoring for GM material at the level of 1.0% or lower. Statistical and immunochemical analyses were carried out in order to assess the relative contributions of various factors to the error observed in these studies. These analyses indicated that limitations in operator performance, not defects in test kit materials, were the primary contributors, while sample size may play a secondary role. As both operator performance and sample size are independent of the specific characteristics of the test kit used in this study, it appears justifiable to generalize conclusions obtained here to other similar test systems.

The lateral flow test (LFT) is an immunochromatographic method that utilises an immunostrip for non-laboratory diagnostic purposes. The present study evaluated a milk progesterone LFT against the enzyme immunoassay (EIA) to confirm oestrus and a non-pregnancy diagnosis. In total, 277 milk samples from 70 cows were analysed, collected on the day of artificial insemination and at 19 days, 21 days and 24 days post insemination. The level of accuracy of the LFT compared with the EIA was 95.0 per cent for milk samples containing2 ng/ml progesterone and 97.0 per cent for milk samples containing10 ng/ml progesterone. The validation of oestrus by the LFT was 98.6 per cent accurate using 2 ng/ml progesterone as the EIA estimate for oestrus. The test performance for a non-pregnancy diagnosis was subject to the day of milk sampling, showing the highest accuracy on day 24 post insemination for both tests. When optimised for maximum specificity, and compared with rectal palpation, the LFT had a sensitivity and specificity for non-pregnancy diagnosis on day 24 post insemination of 75.0 per cent and 100.0 per cent, respectively, with an overall accuracy of 84.4 per cent. The corresponding characteristics for the quantitative EIA were 85.0 per cent, 100.0 per cent and 90.6 per cent, respectively. The LFT results compared favourably with the quantitative milk progesterone EIA.