Confirmatory testing of 120 positive HIV antibody screening samples in Lanxi City / 预防医学

Objective@#To analyze the confirmatory test results of 120 positive HIV antibody screening samples in Lanxi City, Zhejiang Province, so as to provide insights into AIDS detection and control. Methods Western blotting confirmatory assay was performed on 120 positive HIV antibody samples from HIV screening laboratories in Lanxi City from 2020 to 2022. The confirmatory test results were determined according to the “National Technical Guidelines for AIDS Testing (2020 revision)” and “Diagnosis for HIV/AIDS” (WS 293-2019), and the positive rate of confirmatory test and band distribution were analyzed. @*Methods @#Western blotting confirmatory assay was performed on 120 positive HIV antibody samples from HIV screening laboratories in Lanxi City from 2020 to 2022. The confirmatory test results were determined according to the “National Technical Guidelines for AIDS Testing (2020 revision)” and “Diagnosis for HIV/AIDS” (WS 293-2019), and the positive rate of confirmatory test and band distribution were analyzed.@*Results@#Among 120 positive HIV antibody screening samples, there were 100 HIV-1 antibody positive samples (83.33%) as revealed by Western blotting confirmatory assay, 6 HIV antibody negative samples (5.00%), and 14 HIV-1 indeterminate tests (11.67%). There were 72 men and 28 men tested positive for HIV-1 antibody, with a male to female ratio of 2.57∶1, and there were 88 patients at ages of 20 to 59 years (88.00%), with the highest frequency of gp160, gp120 and p24 bands (100.00%). The most common Western blotting band pattern was p24 among HIV-1 indeterminate tests (78.57%). Among all HIV-1 indeterminate Western blotting tests, 6 cases were tested positive for HIV-1 antibody (gp160+p24) and 8 cases tested negative for HIV antibody during the follow-up period. @*Conclusions@# The prevalence of HIV-1 antibody was 83.33% in 120 positive HIV antibody screening samples in Lanxi City. The three most common Western blotting band patterns were gp160, gp120 and p24. The follow-up requires to be reinforced in HIV-1 indeterminate Western blotting tests for early identification and early intervention.

Screening and confirmatory test of HTLV in blood donors, apreliminary study / 中国输血杂志

【Objective】 To study the screening and confirmatory test of human T-lymphotropic virus(HTLV) in blood donors. 【Methods】 Anti HTLV-1 / 2 screening was conducted on voluntary blood donors from 9 cities in Fujian province betweenJan. 12016toDec. 312018.Plasma samples ofanti-HTLV-1/2 reactive donors werecollected and sent to Xiamen Blood Center for confirmatory test. The influence of different screening reagents and confirmatory test methods on the test results were analyzed. 【Results】 A total of 741 anti-HTLV-1/2 reactivesamples were collected, among which 252 were positiveby Western Blot, 15undetermined, and 474negative, withthe overall positive rate at 34.0% (252/741). The yielding rate of domestic reagent A was significantly differentbyregions, withthe highest in Ningde(73.9%, 88/119) and the lowest in Zhangzhou(4.0%, 4/99). The confirmedpositive rates of anti-HTLV-1/2 screening reagent A(domestic) and B(imported)were 33.3%(13/39) and 57.1%(56/98), respectively, and the difference was statistically significant(P5, the reagent Ayielding rate was 76.5%(13/17), significantly lower than that of imported reagent Bas 100%(56/56) (P<0.01). A total of 652 anti-HTLV-1 / 2 reactive samples were confirmed by Western Blot and nucleic acid test in parallel, among which 638 results were concordant, 14 were not, with the overall concordance rate at 97.85%. 【Conclusion】 Comparable differences in the yielding rate of twoanti-HTLV screening reagents were observed.There was over allhighconcordance, but also complementarity, between Western Blot and nucleic acid test.

Re-evaluation of screening and confirmatory tests in primary aldosteronism / 中华内分泌代谢杂志

Prevalence of primary aldosteronism (PA) ranges from 5%to 10%in hypertensive patients. The diagnostic process of PA includes screening, confirmation, and subtype classification. In this manuscript, the recently published data from China regarding to screening and confirmatory tests were summarized, and some important instructions of screening and confirmatory tests were emphasized for improving clinical practice.

Analysis on results of HCV screening among volunteer blood donors in Guiyang area / 重庆医学

Objective To analyze and compare the anti-HCV reactivity,HCV nucleic acid detection results and HCV recom binantion immunoblot assay(RIBA) confirmatory test results in blood donors.Methods The blood samples collected from the volunteer blood donors from October 2013 to March 2015 were performed the HCV screening by using the domestic ELISA reagents from two different manufacturers and an imported nucleic acid detection reagent and matching detection system.The samples of anti-HCV reactivity or/and NAT detection positive were performed RIBA.Then the results of reactivity detected by two kinds of ELISA reagents,nucleic acid detection reagent and RIBA confirmatory test results were analyzed and compared.Results A total of 133959 samples of volunteer blood donors were detected,in which 113 380 samples covered the nucleic acid detection results,the reactivity samples proportion of anti-HCV detection was 0.19 ％ (252/133959),27 cases were positive in NAT detection with the positive detection ratio of 0.02 ％ (27/113 380);the proportion of HCV reactive samples confirmed by RIBA was 19.8 ％ (50/252),the negative proportion was 54.8％ (138/252),and the uncertain proportion was 25.4％ (64/252);27 samples of nucleic acid detection positive were double reagent reactivity in ELISA detection and positive in confirmatory test.The difference among the results of two ELISA reagents,RIBA confirmatory test results and nucleic acid detection results had statistical significance(P＜0.05).Conclusion The detection strategy selecting twice ELISA+1 kind of nucleic acid detection is more secure.Aiming at higher proportion of false positive samples,the follow up system of blood donors should be established for maximizing the retention of blood donors.

ESBL- A continuous diagnostic challenge to clinical microbiology laboratories.

Objectives: Extended spectrum beta lactamase (ESBL) producers have posed a great threat to the use of many classes of antibiotics, particularly cephalosporins. Their detection has proved to be difficult for many laboratories because the resistant ESBL producing organisms appear to be susceptible by in vitro routine testing but result in treatment failure.The present study aims to detect the prevalence of ESBLs in organisms like E.coli and Klebsiella spp. which are responsible for many serious infections. Method: Isolates were screened for ESBL production using cefotaxime, ceftazidime and ceftriaxone by disk diffusion method. Isolates showing resistance to one or more than one of these drugs were futher subjected to Phenotypic Confirmatory Test (PCT) using CAZ/CAZ-CAC as per CLSI guidelines. Results: Of the 230 isolates, 116 (50.43%) tested positive by initial screening method. But on PCT only 94 tested positive. Out of 94 ESBL producers, 59 (62.76%) were E.coli and 35(37.23%) were Klebsiella spp. Of the various clinical samples urine 90(39%) showed maximum number of ESBL producers (32, 34%), followed by pus (27, 29%). Out of 230, 126 (54.7%) were females and 104 (45.2%) were males with a male to female ratio of 0.82:1 showing female preponderance. This study also showed increasing resistance to fluoroquinolones among ESBL producers. Conclusion: The results of our study show that there is an increased prevalence of ESBL producers in our tertiary care centre and also an increased resistance to fluoroquinolones among ESBL producers. Hence infections caused by E.coli and Klebsiella spp. which are prime producers of ESBL have to be considered seriously and proper screening methods and antibiotic policies have to be drawn to confine their spread.

True Hepatitis B Virus Surface Antigen Prevalence among Korean Blood Donors / 대한수혈학회지

BACKGROUND: The sensitivity of the blood screening test is crucial to ensure blood safety. Generally the test methods with greater sensitivity tend to have lower specificity. Therefore, secondary confirmatory tests are required to solve this problem. Since the confirmatory test for hepatitis B virus surface antigen (HBsAg) has not been routinely applied yet in Korea for blood donors, the true positive rate of HBsAg is unknown. This study was intended to determine the true seroprevalence of the hepatitis B virus (HBV) among Korean blood donors. METHODS: A total of 906 blood donor samples found to be positive for HBsAg with Prism qualitative assay from November 2010 to April 2011 at Korean Red Cross blood centers were tested with Architect HBsAg qualitative assay and confirmatory assay. Blood samples with negative results using Architect HBsAg qualitative assay were tested with Prism HBsAg confirmatory test. RESULTS: Of the 906 samples positive by Prism HBsAg qualitative assay, 793 were confirmed as positives. The positive predictive value of Prism HBsAg qualitative assay was 87.5%, and the true seroprevalence of HBV among Korean blood donors was 8 out of 100,000. The sample-to-cut-off ratio (S/CO) value of one true positive sample was lower than 1. CONCLUSION: The positive predictive value of HBsAg by Prism was higher than expected. Baseline data for estimation of residual risk of HBV as well as the cost-effectiveness analysis for lookback policy were drawn. Finally, the current cut-off level for repeat assay looked reasonable and it should be maintained at least until the nucleic acid amplification test is implemented as a routine screening method.

Importância dos testes sorológicos de triagem e confirmatórios na detecção de doadores de sangue infectados pelo vírus da hepatite C / Importance of screening and confirmatory tests to detect blood donors infected by the hepatitis C virus

A triagem sorológica de doadores de sangue com baixos índices de prevalência de infecção, como no caso da hepatite C (HCV), gera um percentual considerável de resultados falso-positivos e descarte de bolsas de hemocomponentes freqüentemente não infectados. O objetivo deste estudo foi pesquisar o perfil sorológico e, com base no teste confirmatório, a ocorrência de hepatite C nos doadores com sorologia positiva ou indeterminada do Hemocentro Regional de Uberaba (HRU). Os testes confirmatórios foram realizados por meio da detecção do RNA do HCV no plasma, utilizando-se o método RT-PCR qualitativa. Foram realizadas, no período de 1992 a 2005, 171.027 doações de sangue no HRU, sendo 24,3 por cento de doadores iniciais e 75,7 por cento de retorno. O índice de inaptidão para HCV foi de 0,3 por cento (561 doações), sendo que 53,0 por cento destas eram de doadores iniciais e 47,0 por cento de retorno, com prevalências de 0,5 por cento e 0,2 por cento, respectivamente (p<0,0001). O índice de reações inconclusivas foi significativamente maior nos doadores de retorno (p=0,0214). Noventa e oito candidatos foram submetidos à PCR qualitativa e apenas 34 (34,7 por cento) apresentaram resultados positivos, com índice de positividade significativamente menor nos doadores de retorno (p=0,0184) e quase três vezes menor nos inconclusivos. Assim, verificamos que grande número de doadores, tanto anti-HCV positivos quanto indeterminados, não tiveram confirmada a presença da infecção pelo HCV, levando-nos a concluir que a inaptidão sorológica para hepatite C no HRU, na maioria das vezes, não correspondeu à presença de infecção viral no doador.

Serological screening of blood donors with low indexes of infection, including hepatitis C virus (HCV), accounts for a substantial percentage of false-positive results with consequent loss of non-infected blood components. The aim of this study was to evaluate the occurrence of hepatitis C using confirmatory tests for blood donors with positive or inconclusive results at Hemocentro Regional de Uberaba (HRU). Confirmatory tests were performed by the detection of HCV RNA in plasma using qualitative RT-PCR. The study was carried out from 1992 to 2005 for 171,027 blood donors, 24.3 percent first-time and 75.7 percent repeat donors. The ineligibility rate to HCV was 0.3 percent (561 donors) with 52.9 percent of them being first-time donors and 47.0 percent repeat donors with prevalences of 0.5 percent and 0.2 percent respectively (p<0.0001). The rate of inconclusive results was significantly higher among repeat donors (p=0.0214). Ninety-eight samples were subjected to qualitative PCR and only 34.7 percent (34) had positive results, with a significantly lower rate of positiveness for repeat donors (p = 0.0184) and almost a threefold lower rate of inconclusive results for the same donors. These results showed that, for a large number of donors with positive and inconclusive tests for anti-HCV, the infection was not confirmed. We concluded that serological ineligibility for hepatitis C of donors at HRU was not always associated with the presence of viral infection.

Evaluation of the Phoenix Automated Microbiology System for Detecting Extended-Spectrum beta-Lactamase in Escherichia coli, Klebsiella species and Proteus mirabilis / 대한진단검사의학회지

BACKGROUND: The aim of this study was to compare the BD Phoenix (Beckton Dickinson Diagnostic Systems, USA) extended-spectrum beta-lactamase (ESBL) test with the Clinical and Laboratory Standards Institute (CLSI) ESBL phenotypic confirmatory test by disk diffusion (CLSI ESBL test) in Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca and Proteus mirabilis. METHODS: We tested 224 clinical isolates of E. coli, K. pneumoniae, K. oxytoca and P. mirabilis during May 2006 to March 2007. These isolates were examined by the Phoenix and the CLSI ESBL tests simultaneously. For the isolates showing discordant results between the two tests, boronic acid disk test was performed to differentiate AmpC beta-lactamase and ESBL. RESULTS: Among the 224 clinical isolates, 75 and 79 isolates were positive for ESBL by CLSI ESBL test and Phoenix test, respectively. Having detected 4 more isolates as ESBL-producers, Phoenix test showed a 98.2% agreement with a 100% sensitivity and 97.3% specificity compared with CLSI ESBL test. Among the four false positive isolates, three were AmpC-positive but ESBL-negative. CONCLUSIONS: The BD Phoenix ESBL test was sensitive and specific, and can be used as a rapid and reliable method to detect ESBL production in E. coli, Klebsiella species, and P. mirabilis.

Study on the indeterminate results of characterization and verification of HIV antibody from Western blot test / 中华流行病学杂志

Objective To study the serological characterization of indeterminate Western blot(WB)results of HIV antibody and to find a new way to verify the HIV antibody indeterminate results and provide references for editing"National Guideline for Detection of HIV/AIDS".Methods All of the 42 subjects who were confirmed as indeterminate HIV antibody in People'Libaretion Amry HIV Confirmation Laboratory from 2005 to 2006,were collected.Line immunoassay.HIV viral load test and HIV-1 p24 were tested and followed up for 3-6 months'to compare the changes of WB bands patterns.Results (1)For the 42 individuals with indeterminate HIV antibody.a total of 8 different patterns of bands were found in WB test including 45.2% of them were p24 monoband,30.9% were gp160 monoband,11.9% were gp160 with p24,2.4%(only one case)were gp160gp120 ±,gp41p24,p24p17,gp41 or gp120respectively.It was noticed that the most patterns of common bands with indeterminate results were p24 monoband.gpl60 monoband and gpl60 with p24.which composed 88.0% of the whole indeterminate WB band patterns.(2)Twenty three cases had been followed up for more than 3 months with 22 giving no WB band image change and were confirmed as HIV sero-negative.The other one with case gp160 and p24 had developed to more bands in the period of 77 days follow-up with more bands,including gpl60,gp120,p66,p31,p24 and p17,showed up and was confirmed as HIV primary infection.(3)Line immunoassay was applied to all of those 23 cases who had been followed up and the results showed that only one serological change was found and the case was confirmed to be HIV-positive.Among the other 22 cases without serological changes.16 cases were proved to be HIV-negative,6 cases were still indeterminate.The specificitv was 72.7%.P24 antigen test showed negative in all the 23 cases,including the case which later was confirmed as HIV-positive.Of all the 23 originally indeterminate cases,viral loads were tested in 7 eases.Positive result was found in the case which was proved later to be HIV-positive.No viral loads were detected in the other 6 cases(＜LDL).Conclusion The most common band patterns of indeterminate HIV antibody were mainly p24 monoband,gp160 monoband or with p24.Most of them (95.6%)were not infected by HIV,the bands showed up in WB test and demonstrated as non-specific reactions.Line immunoassay could determine about 70% of the indeterminate reactions.Results from viral load test also suggested that it was an efficient method to discriminate indeterminate results.With these two techniques,HIV serology could be diagnosed without 3 months'follow-up in primary infection which gave indeterminate WB results.