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Background: Human respiratory syncytial virus (RSV) is a leading cause of acute lower respiratory tract infection and hospitalization, especially in children. Highly mutagenic nature and antigenic diversity enable the RSV to successfully survive in human population. We conducted a molecular epidemiological study during 2017–2021 to investigate the prevalence and genetic characteristics of RSV. Methods: A total of 6499 nasopharyngeal (NP) swabs were collected from hospitalized children at Department of Pediatrics, Guangdong Provincial Hospital of Traditional Chinese Medicine, Guangzhou, Guangdong, China. All NP swab specimens were preliminary screened for common respiratory viruses and then tested for RSV using specific PCR assays. Partial G genes of RSV were amplified for phylogenetic analysis and genetic characterization. Results: The overall detection rate for common respiratory viruses was 16.12% (1048/6499). Among those, 405 specimens (6.20%, 405/6499) were found positive for RSV. The monthly distribution of RSV and other respiratory viruses was variable, and the highest incidence was recorded in Autumn and Winter. Based on the sequencing of hypervariable region of G gene, 93 RSV sequences were sub-grouped into RSV-A (56, 60.2%) and RSV-B (37, 39.8%). There was no coinfection of RSV-A and RSV-B in the tested samples. Phylogenetic analysis revealed that RSV-A and RSV-B strains belonged to ON1 and BA9 genotypes respectively, indicating predominance of these genotypes in Guangzhou. Several substitutions were observed which may likely change the antigenicity and pathogenicity of RSV. Multiple glycosylation sites were noticed, demonstrating high selection pressure on these genotypes. Conclusion: This study illustrated useful information about epidemiology, genetic characteristics, and circulating genotypes of RSV in Guangzhou China. Regular monitoring of the circulating strains of RSV in different parts of China could assist in the development of more effective vaccines and preventive measures. [ABSTRACT FROM AUTHOR]

Purpose: We aimed to describe the vitamin D status and its distribution in different age groups, sexes, seasons, and provinces of a large Chinese population. Methods: This study retrospectively analyzed 1,528,685 results of serum 25-hydroxyvitamin D (25(OH)D) in the central laboratory of KingMed Diagnostics. The samples were from the individuals aged 0–119 years old in 30 provinces of China. Serum 25(OH)D was measured by an accurate commercial liquid chromatography-tandem mass spectrometry (LC–MS/MS) method from January 2017 to December 2019. The subjects were stratified by age, sex, the season of blood collection, and the province of residence. Results: The median 25(OH)D concentration was 25.5 ng/mL (interquartile range (IQR) 18.7–32.7 ng/mL) in males and 20.8 ng/mL (IQR 14.4–28.2 ng/mL) in females. Overall, the median 25(OH)D concentration decreased with age in both males and females. Males had a 0.2–2.4 ng/mL higher median 25(OH)D concentration than females in different age groups. Vitamin D deficiency (25(OH)D < 15 ng/mL for the individuals under 14 years old; < 20 ng/mL for the individuals over 14 years old) was found in 21.3% of males and 43.6% of females. Significant seasonal variation of serum 25(OH)D concentrations was repeatedly observed in 3 years, with median concentration higher in summer (25.3 ng/mL (IQR 19.3–31.9 ng/mL)) and lower in winter (18.5 ng/mL (IQR 12.3–26.6 ng/mL)). Vitamin D status varied by province. The median 25(OH)D concentration was the highest in Hainan (31.0 ng/mL (IQR 24.9–39.2 ng/mL)) and the lowest in Qinghai (14.4 ng/mL (IQR 9.6–20.0 ng/mL)). 25(OH)D2 was detected in 12.2% of the results, and no significant seasonal variation was observed. Conclusion: In China, vitamin D deficiency is prevalent in the population participating in clinical vitamin D measurement. Age and sex differences in vitamin D levels were observed in our study. Seasonal variation and provincial differences are important aspects of serum vitamin D status. 25(OH)D2 cannot be ignored entirely in clinical measurement practice in China. [ABSTRACT FROM AUTHOR]

Streptococcus agalactiae colonization in pregnant women can cause postpartum intrauterine infections and life-threatening neonatal infections. To formulate strategies for the prevention and treatment of S. agalactiae infections, we performed a comprehensive analysis of antibiotic resistance and a molecular-based epidemiological investigation of S. agalactiae in this study. Seventy-two S. agalactiae strains, collected from pregnant women, were subjected to antibiotic susceptibility tests; then, the screened erythromycin and clindamycin nonsusceptible isolates were used for macrolides and clindamycin resistance genes detection, respectively. Detection of resistance genes, serotyping, and determination of virulence genes were performed by polymerase chain reaction. The clonal relationships among the colonized strains were evaluated by multilocus sequence typing. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) mass peak analysis was performed to discriminate the specific sequence types (STs). In our study, 69.4% and 47.2% of the strains were nonsusceptible to erythromycin and clindamycin, respectively; the multidrug resistance rate was 66.7%. All erythromycin nonsusceptible strains harbored resistance genes, whereas only 52.9% of the clindamycin nonsusceptible strains possessed the linB gene. Erythromycin resistance was mainly mediated by the ermB or mefA/E genes. Four serotypes were identified, and the most common serotype was serotype III (52.8%), followed by Ib (22.2%), Ia (18.0%), and II (4.2%). All the strains were divided into 18 STs that were assigned to nine clonal complexes. Most of the major STs were distributed into specific serotypes, including ST19/serotype III, ST17/serotype III, ST485/serotype Ia, ST862/serotype III, and ST651/serotype III. Analysis of virulence genes yielded seven clusters, of which bca-cfb-scpB-lmb (61.6%) was the predominant virulence gene cluster. Among all ST strains distributed in this region, only the ST17 strains had a mass peak at 7620 Da. The outcomes of this study are beneficial for the epidemiological comparison of colonized S. agalactiae in different regions and may be helpful for developing the strategies for the prevention of S. agalactiae infection in Guangzhou. Furthermore, our results show that MALDI-TOF MS can be used for the rapid identification of the ST17 strains. [ABSTRACT FROM AUTHOR]

Objective: We aimed to describe the 25-hydroxyvitamin D (25(OH)D) status of southern Chinese individuals by a high-accuracy liquid chromatography tandem mass spectrometry (LC-MS/MS) method which can trace to reference measurement procedure. Materials and methods: From January 2018 to June 2019, a total of 4775 southern Chinese individuals were evaluated in our study. The serum levels of parathyroid hormone (PTH) were detected simultaneously in 162 cases. 25(OH)D was determined by LC-MS/MS, and PTH was detected using routine automated analysers. The distribution of the concentration, prevalence and seasonal variability of 25(OH)D in males and females of different age groups were studied. Results: The mean 25(OH)D concentration in our study was 32.57 ng/mL (4.20–101.40 ng/mL). The global 25(OH)D concentration in males was higher than that in females of different age group. The prevalence of vitamin D deficiency (< 20 ng/mL) in females (16.65%) was higher than that in males (6.83%). The prevalence of vitamin D deficiency (< 20 ng/mL) was most common in winter (22.98% of all women and 15.49% of all men). 25(OH)D concentrations were higher in those from whom blood samples were collected in summer and autumn than in winter and spring. 25(OH)D2 was detected in 672 serum samples (14.07%). In addition, there was a negative correlation between the concentrations of 25(OH)D and serum PTH (r = − 0.149, P < 0.05). Conclusion: Our study demonstrated that the average serum 25(OH)D concentration in southern Chinese individuals was higher than that in other Chinese cohorts by a high-accuracy LC-MS/MS method. The global 25(OH)D concentration in males was higher than that in females of different ages, and the prevalence of vitamin D deficiency in females was higher than that in males. Seasonal change was an important aspect of 25(OH)D concentration in young and middle-aged people but became less relevant for that in older subjects. 25(OH)D2 detection was of minor practical significance in our study. In addition, we also found that there was a negative correlation between the serum levels of 25(OH)D and PTH in southern Chinese individuals. [ABSTRACT FROM AUTHOR]

An amendment to this paper has been published and can be accessed via the original article. [ABSTRACT FROM AUTHOR]

• A highly reliable, sensitive, accurate, and precise ID-LC–MS/MS-based candidate reference measurement procedure for E 2 measurement was developed and validated. • Bracketing calibration method (BCM) compared to classical calibration curve. • BCM has demonstrated to be higher accurate and precise and in good agreement with the need of RMPs. • Sample preparation requires no derivatization, and appropriate retention of E 2 and high resolution of structural analogs were achieved within a short time span. • The validated method was successfully applied to measure the E 2 level in serum samples and to assess the accuracy of three immunoassays in a clinical laboratory. A highly accurate liquid chromatography tandam mass spectrometry (LC–MS/MS) based candidate reference measurement procedure (cRMP) for the determination of human serum 17β-estradiol (E 2) was developed. A bracketing calibration method (BCM) based on internal standard (IS) concentrations for each sample used to best match the analyte concentration was compared to the classical calibration curve-based method with a constant IS concentration. Precision was analyzed according to the inter-assay reproducibility (n = 15) and intra-assay repeatability (n = 9). Accuracy was confirmed using certified reference materials (CRMs) and further validated by comparison to the established RMPs. Sixty patient serum samples were collected, and the E 2 levels were measured by the BCM isotope dilution (ID) procedure coupled with the LC–MS/MS method to evaluate three immunoassays commonly used in clinical laboratories in China. Limits of quantification (LoQ) as low as 5 pg/mL (18 pmol/L) were achieved. The isomer of E2 (17α-estradiol) was successfully separated by optimizing the LC method. The results of method validation showed that the intra- and inter-assay imprecisions were 1.84 ∼ 2.91% vs 2.08 ∼ 9.53%, while the analytical recoveries were 98.73 ∼ 100.77% vs 93.72 ∼ 102.39% for the BCM and classical calibration curve quantification method, and the BCM demonstrated a higher agreement with CRMs and established RMPs. Bland-Altman plots of the E 2 results revealed concentration-dependent biases. In conclusion, a precise, facile, and reliable ID-LC–MS/MS method is developed in this study. It is demonstrated that the use of the BCM could achieve higher precision and accuracy, which better meet the needs of RMPs. [ABSTRACT FROM AUTHOR]

Objective: Researches on the epidemiology of various respiratory pathogens at multiple testing points in the pediatric population are limited, and these are crucial for the prevention of respiratory tract infections in children., Methods: We obtained 1788 upper respiratory tract swabs from children exhibiting symptoms of respiratory infection (notably fever with a body temperature exceeding 38.5°C) across five hospitals in Guangdong between November 2020 and June 2022. We used the multiplex probe amplification (MPA) PCR testing to identify 11 respiratory viruses and subsequently analyzed the prevalence characteristics of these pathogens among febrile children in hospitals., Results: The overall detection rate of the pathogens was 58.1% (1039/1788). Human rhinovirus (HRV) exhibited the highest detection rate at 19.0% (339/1788), succeeded by human parainfluenza virus (HPIV), human adenovirus (HAdV), and respiratory syncytial virus (RSV). The positivity and coinfection rates were higher in children aged 5 years and below compared to those above 5 years. Moreover, a distinct pathogen spectrum was observed across different age groups. Hospitalized patients demonstrated a significantly higher positivity and coinfection rate compared to outpatients. During COVID-2019, RSV appeared a counter-seasonal trend., Conclusion: Respiratory viral infections in children display distinct characteristics concerning age, hospitalization status, and seasonality. Children under the age of 5 and minor patients admitted to hospitals at least be tested for RSV, HRV, HPIV, and HAdV. The epidemiological patterns of RSV in the post-epidemic period require ongoing surveillance., (© 2024 The Author(s). The Clinical Respiratory Journal published by John Wiley & Sons Ltd.)

Background: The aim of this study is to verify the analytical performance of four homocysteine detection systems made in China and to explore the comparability of homocysteine detection systems by isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) reference method., Methods: The intra-batch precision, inter-batch precision, accuracy, and linear range of four homocysteine detection systems were evaluated. The ID-LC-MS/MS reference method was used to evaluate the comparability and accuracy of fresh frozen serum samples in four different detection systems of homocysteine. The ID-LC-MS/MS reference method is used to assign samples as calibrators to calibrate each system. The variation and deviation of fresh serum samples between different systems before and after calibration were compared., Results: The intra-batch imprecision of the four detection systems was less than 5%, and the coefficient of variation of inter-batch imprecision was less than 6.7%. The precision met the clinical requirements. Before calibration, the results measured by detection system 2 are consistent with the ID-LC-MS/MS reference method, which meets the requirements of accuracy verification. The regression equation of R² ≥ 0.975 in the regression equation of linear analysis of the four systems, the linearity of the four detection systems is good in the range of evaluation concentration, and all of them can meet the declared linear range. The absolute average bias of fresh serum measured by the four detection systems after calibration decreased from 3.76 μmol/L, 0.96 μmol/L, 1.30 μmol/L, -1.56 μmol/L to 0.31 μmol/L, 0.28 μmol/L, 0.4 μmol/L, 0.40 μmol/L, respectively. The relative average bias decreased from 22.6%, 7.50%, 11.0% and -8.50% to 1.98%, 1.78%, 2.59%, 2.34%, respectively. After calibration, the slope and intercept of the regression curve of the fresh serum measured by the four detection systems and the reference method are closer to 1 and 0 than before calibration., Conclusions: The precision, reference interval, and linear evaluation of the four detection systems are good. The ID-LC-MS/MS reference method assigning fresh frozen serum samples as calibrators can improve the accuracy and comparability of the results of different detection systems.

Background: To detect the serum antibodies against respiratory viruses and atypical pathogens in adults with community-acquired pneumonia (CAP) in Guangzhou City (Guangdong province, China)., Methods: A retrospective study was carried out with samples from 685 adults who were admitted with CAP and 108 non-CAP control patients. Atypical pathogens and respiratory viruses in serum were detected using the Pneumoslide IgM test from Vircell, Spain. All patients were divided into 6 groups according to age: 18-24, 25-44, 45-59, 60-74, 75-89, and >90., Results: The total positive rate of CAP was 35.4%, which was highest in the 18-24 age group (P < .05). The highest positive rate, 17.11%, was observed for Mycoplasma pneumoniae (MP). The mean age of MP-infected patients was higher than that of the controls (P < .05). The positive rates for influenza B (INFB), Legionella pneumophila (LP1), Coxiella burnetii (COX), influenza A (INFA), parainfluenza virus (PIV), respiratory syncytial virus (RSV), Chlamydophila pneumoniae (CP), and adenovirus (ADV) were 5.56%, 3.07%, 2.63%, 2.34%, 1.90%, 1.61, 0.88%, and 0.29%, respectively. There were 4.37% of patients with CAP having multiple infections. The main symptoms observed in the 685 CAP patients were cough and sputum production, in 78.4% and 67.4%. Fever was followed by 54% of CAP patients. Dyspnea (39.1%), anorexia (36.8%), increased thirst (26.7%), chills (18.7), headache (14.6%), and nausea (13.1%) were also frequently observed in the CAP patients., Conclusions: MP infection was the most common in adult CAP patients in Guangzhou City with the highest positive rate in the 18-24 age groups., (© 2020 The Authors. Journal of Clinical Laboratory Analysis Published by Wiley Periodicals LLC.)

Purpose The aim of this study was to determine the rate of deafness gene mutations in the Foshan area of South China. Method We enrolled the infants delivered in Foshan Maternity and Children's Healthcare Hospital. Deafness gene mutation was detected by HibriMax method. Our study tested 47,538 newborns within 3 days after birth, including 13 sites in four genes: GJB2 (c.35 del G, c.176 del 16, c.235 del C, c.299 del AT, c.155 del TCTG), GJB3 (c.583 C>T), SLC26A4 (c.2168 A>G, c.919-2 A>G, c.1299 C>T), and mtDNA 12S rRNA (m.1555 A>G, m.1494 C>T, m.12201 T>C, m.7445 A>G). The birth condition of infants was collected, including sex, low or high birth weight, twins, and premature delivery. Results In a total of 47,538 newborns, 1,415 were positively identified with deafness gene mutations. The total rate of the deafness gene mutation was 2.976%. The carrier rates of GJB2 (c.35 del G, c.176 del 16, c.235 del C, c.299 del AT, c.155 del TCTG), GJB3 (c.583 C>T), SLC26A4 (c.2168 A>G, c.919-2 A>G, c.1299 C>T), and mtDNA 12S rRNA (m.1555 A>G, m.1494 C>T, m.12201 T>C, m.7445 A>G) mutations were 0.000%, 0.048%, 1.422%, 0.185%, 0.000%, 0.076%, 0.116%, 0.755%, 0.160%, 0.187%, 0.021%, 0.000%, and 0.006%, respectively. Conclusions Our study showed that the c.235 del C GJB2 mutation was the leading deafness-related mutation in the Foshan area of South China. Deafness gene mutations screening in newborns detected by bloodspot-based genetic screening tests can help the diagnosis of newborn congenital hearing loss.

Background: Our multicenter clinical trial study for stage 4 chronic kidney disease (CKD) populations was conducted at 21 centers in China during the period 2011 to 2016. The CKD definition is based on glomerular filtration rate (GFR) values which can be estimated by creatinine-based predictive formulas. The validity and reliability of GFR estimation is thus largely dependent on the accurate and precise serum creatinine (SCr) measurements. As an integral part of this multicenter study, it is important to ensure the precision, accuracy, and center-to-center comparability of the SCr results., Methods: Prior to initiating the study, we unified the measurement method of SCr determination as an enzymatic method and standardized the procedure in all of the laboratories. Then, the analytical performance of each analyzer at each laboratory was evaluated, including precision, accuracy, and comparability., Results: All within-run and total CVs of the low and high level internal quality control (IQC) were comprised between 0.2% and 4.1% (< 1/3 CLIA'88). Total error of the IQC fall within the maximum 12% at all centers. The analytical bias against the Standard Reference material 967a target was less than ± 0.5% at Central Laboratory, indicating good accuracy. Correlation between the analyzers and the reference method were very high (r > 0.99). Passing-Bablok regression showed no significant deviation from linearity (p > 0.05). Bland-Altman analysis also showed good agreement (≥ 95% of results fell within the 95% limits of agreement)., Conclusions: Performance evaluation helped in addressing preanalytical variations in measurement and gave op-timal quality assurance of laboratory measurement in the context of a multicenter clinical trial study.