Analytical and clinical performance evaluation of a new NT-proBNP assay.

BACKGROUND: The study evaluated the performance of the Mindray N-terminal pro-B-type natriuretic peptide (NT-proBNP) in a healthy population in China, focusing on creating a reference range for future clinical applications adjusted according to different demographics. METHODS: The study measured NT-proBNP in 2277 healthy individuals. We analyzed age and sex-stratified data, performed precision, accuracy, linearitcvy, and detection limit studies, and evaluated method comparison and consistency between Roche and Mindray assays on 724 serum samples. We used Excel 2010, Medcalc, and GraphPad Prism 9. RESULTS: In males, the 97.5th centile NT-proBNP concentration at age < 45, 45 to 54, 55 to 64, 65 to 74 and ≧ 75 were 89.4 ng/L, 126 ng/L, 206 ng/L, 386 ng/L and 522 ng/L, respectively. In females, the concentration of NT-proBNP at the same age was 132 ng/L, 229 ng/L, 262 ng/L, 297 ng/L and 807 ng/L, respectively. The repeatability precision coefficient of variation (CV%) for NT-proBNP was between 0.86 and 1.65 in analytical performance. In contrast, the reproducibility precision (CV%) for NT-proBNP was between 1.52 and 3.22, respectively. The study found a bias of accuracy of 3.73% in low-value samples (concentration: 148.69) and 7.31% in high-value samples (concentration: 1939.08). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 125 ng/L were 96.6%, 92.3%, 84.2%, and 98.5%, respectively. In contrast, those of 300 ng/L were 94.0%, 98.2%, 95.7% and 97.5%, respectively. CONCLUSIONS: The Mindray NT-proBNP assay showed increased levels in both males and females with age, with higher levels in women. It performs well and aligns with manufacturer specifications. We recommend adjusting cutoff values based on demographic factors.

Comparison on the consistency of Mindray and Siemens chemiluminescence analyzers for detecting FT3, FT4 and TSH in patients with hyper- and hypothyroidism.

Background: To examine the consistency of the Mindray and Siemens full-automatic chemiluminescence analyzers in detecting serum free triiodothyronine (FT3), free thyroxine (FT4) and thyroid stimulating hormone (TSH) in patients with hyper- or hypothyroidism. Methods: Included in this study were 164 new patients with abnormal thyroid function assessed at Nan Fang Hospital of Southern Medical University in 2021: 107 patients with hyperthyroidism and 57 with hypothyroidism. Additional 100 healthy individuals comprised the control group. Consistency of the FT3, FT4 and TSH results from the two systems in the different groups was analyzed by Kappa, linear correlation, regression, Bland-Altman and area under the receiver operating characteristic curve (AUC). Results: Compared with the control group, FT3 and FT4 levels were increased and TSH level was decreased in the hyperthyroid group (both P<0.05), whereas FT3 and FT4 levels were decreased and TSH level was increased in the hypothyroidism group (both P<0.05), suggesting that both test systems could provide references for relevant clinical evaluation. Kappa analysis showed high consistency of the two systems in detecting FT3, FT4 and TSH in both hyper- and hypothyroidism patients (mean Kappa value >0.7). In addition, there was a good linear correlation between the test results of the two systems (R2>0.90). Bland-Altman consistency analysis showed that most mean difference values were within the consistency limit (x±1.96s), indicating that the difference between the two systems was acceptable. AUC of FT3, FT4 and TSH detected by the two systems was higher than 0.80 in each group, showing no significant difference between them (both P>0.05), and the difference in sensitivity and specificity was within the acceptable range. Conclusions: Mindray and Siemens chemiluminescence analyzers are highly consistent in detecting FT3, FT4 and TSH in both hyper- and hypothyroidism patients.

Epidemiological and clinical characteristics of respiratory viruses in 4403 pediatric patients from multiple hospitals in Guangdong, China.

BACKGROUND: Acute respiratory infections (ARI) cause considerable morbidity and mortality worldwide, especially in children. Unfortunately, there are limited multi-center data on common viral respiratory infections in south China. METHODS: A total of 4403 nasal swabs were collected from children in 10 cities in Guangdong, China in 2019. Seven respiratory viruses, influenza A virus (IFA), influenza B virus (IFB), respiratory syncytial virus (RSV), adenoviruses (ADV) and parainfluenza virus types 1-3 (PIV1, PIV2 and PIV3), were detected by direct immunofluorescence antibody assay. The personal information and clinical characteristics were recorded and analyzed. RESULTS: The results showed that at least one virus was detected in 1099 (24.96 %) samples. The detection rates of RSV, IFA, ADV, PIV3, PIV1 and PIV2 were 7.13 % (314/4403), 5.31 % (234/4403), 4.02 % (177/4403), 3.04 % (134/4403), 1.70 % (75/4403) and 1.16 % (51/4403), respectively. The detection rate of RSV was highest in 0-6-month-old children at 18.18 % (106/583), while the detection rate of IFA was highest in 12-18-year-old children at 20.48 % (17/83). The total detection rates in winter and spring were 35.67 % (219/614) and 34.56 % (403/1166), higher than those in summer, 17.41 % (284/1631), and autumn, 19.46 % (193/992). CONCLUSIONS: RSV and IFA were the main respiratory viruses in children. With increasing age the detection rate of RSV decreased in children, but the trends for the detection rates of IFA and IFB were the opposite. This study provided the viral etiology and epidemiology of pediatric patients with ARI in Guangdong, China.

Corrigendum: Thymic Epithelial Cells Contribute to Thymopoiesis and T Cell Development.

[This corrects the article DOI: 10.3389/fimmu.2019.03099.].

Thymic Epithelial Cells Contribute to Thymopoiesis and T Cell Development.

The thymus is the primary lymphoid organ responsible for the generation and maturation of T cells. Thymic epithelial cells (TECs) account for the majority of thymic stromal components. They are further divided into cortical and medullary TECs based on their localization within the thymus and are involved in positive and negative selection, respectively. Establishment of self-tolerance in the thymus depends on promiscuous gene expression (pGE) of tissue-restricted antigens (TRAs) by TECs. Such pGE is co-controlled by the autoimmune regulator (Aire) and forebrain embryonic zinc fingerlike protein 2 (Fezf2). Over the past two decades, research has found that TECs contribute greatly to thymopoiesis and T cell development. In turn, signals from T cells regulate the differentiation and maturation of TECs. Several signaling pathways essential for the development and maturation of TECs have been discovered. New technology and animal models have provided important observations on TEC differentiation, development, and thymopoiesis. In this review, we will discuss recent advances in classification, development, and maintenance of TECs and mechanisms that control TEC functions during thymic involution and central tolerance.

Reflex threshold of signal-to-cut-off ratios of the Elecsys anti-HCV II assay for hepatitis C virus infection.

INTRODUCTION: Fast screening tests for hepatitis C virus (HCV) antibody often give false-positive results. Signal-to-cut-off (S/Co) ratios were suggested to be used as reflex confirmation of anti-HCV. The Elecsys Anti-HCV II assay is an effective test for the detection of hepatitis C, but no S/Co cutoff has been reported. The aim of this study was to determine the S/Co ratio threshold of anti-HCV test using Elecsys Anti-HCV II screening and supplemental recombinant immunoblot assay (RIBA) test results as the gold standard. METHODOLOGY: A total of 36,341 serum samples were tested for HCV antibody using the Elecsys Anti-HCV II assay and 276 positive samples were then tested with supplemental RIBA (Mikrogen recomLine HCV IgG strip immunoassay). Receiver operation curve (ROC) analysis was used to determine the cutoff, sensitivity, and specificity of the optimal S/Co ratio. RESULTS: The Elecsys Anti-HCV II assay was positive (S/Co ratio ≥ 1) in 288 of the 36,341 samples (0.79%). RIBA testing on 276 of these 288 positive samples showed that all but one of 44 samples with an S/Co ratio of ≥ 1 and < 10 were negative, whereas the vast majority of samples (223/232, 96.1%) with an S/Co ratio ≥ 10 were positive. ROC analysis revealed that an optimal S/Co ratio cut-off value was 12.27. CONCLUSIONS: An S/Co ratio of 12.27 obtained with the Elecsys Anti-HCV II assay could be used as reflex confirmation of anti-HCV tests.

[Changes of serum N-terminal pro-brain natriuretic peptide levels in patients with cardiovascular diseases and its clinical significance].

OBJECTIVE: To detect the changes in serum N-terminal pro-brain natriuretic peptide (NT-proBNP) levels in patients with cardiovascular diseases and explore its clinical significance. METHODS: Serum NT-proBNP concentrations were measured by electrochemiluminescent immunoassay (ECLIA) in 460 patients with cardiovascular diseases and in 50 normal controls, and echocardiographic examination was performed to determine the left ventricular ejection function (LVEF). Analysis of NT-proBNP was performed for its correlation to New York Heart Association (NYHA) functional classifications LVEF, and risk factors of cardiovascular diseases. RESULTS: The serum LgNT-proBNP concentrations was 3.74 in patients with cardiovascular diseases, significantly higher than that of normal controls (1.42, P<0.001). NT-proBNP concentrations also varied significantly among patients with different cardiovascular diseases as shown by one-way ANOVA analysis (F=17.761, P<0.001). The NT-proBNP levels increased with the severity of heart failure according to NYHA functional classifications (P<0.001), and varied significantly in patients suffering different cardiovascular diseases with the same NYHA functional class. Multivariable regression analysis indicated there were significant correlations of NT-proBNP levels with the patients' age (r=0.152, P<0.001), NYHA functional classifications (r=0.725, P<0.001), LVEF (r=-0.634, P<0.001), and clinica outcomes (r=-0.581, P<0.001). Logistic regression analysis identified NT-proBNP level as a strong indicator for cardiovascular events (HR=2.763, P<0.01) with close correlation to the treatment results. CONCLUSIONS: Serum NT-proBNP level varies significantly with the severity of heart failure and can be indicative of the patients' cardiac function in close correlation to the clinical prognosis, but its value for diagnostic stratification of cardiovascular diseases awaits further investigation.