Third-generation Enzyme Immunoassay Research Articles

Seroprevalence of Trypanosoma cruzi among children from Veracruz, Mexico: Epidemiological baseline for a control model based on Chagas disease active transmission

Introduction. In 2021, the Secretaría de Salud de México and the Pan American Health Organization launched an initiative to interrupt intra-domiciliary vector transmission of Trypanosoma cruzi based on the prevalence of Chagas disease in children. The Mexican State of Veracruz was leading this initiative. Objective. To estimate the seroprevalence of T. cruzi infection among children under 15 years of age from rural areas of Veracruz, México. Materials and methods. We identified eight localities of high priority from the Municipality of Tempoal, Veracruz, for baseline serology. Blood samples were collected on filter paper from 817 individuals between June and August 2017, for screening with a third-generation enzyme immunoassay. Reactive cases were confirmed by indirect hemagglutination, enzyme-linked immunosorbent assay, and indirect immunofluorescence tests on peripheral blood serum samples. We calculated seroprevalence and 95% confidence intervals (CI). Results. We confirmed Chagas disease cases in children under 15 years of age with a seroprevalence of 1,9% (95 % CI = 1,12-3,16) in the localities of Citlaltepetl, Cornizuelo, Cruz de Palma and Rancho Nuevo. Conclusions. These results indicate recent transmission of T. cruzi in these communities and allow to establish an epidemiological baseline for the design and implementation of a model focused on geographical areas with active transmission to advance toward the elimination of intra-domiciliary vector transmission of this parasite in Mexico.

Prevalence of hepatitis B virus infection among general population of Armenia in 2021 and factors associated with it: a cross-sectional study

ObjectivesThis study sought to determine the prevalence and associated factors of hepatitis B virus (HBV) infection ever in life and chronic HBV infection in Armenia.DesignA population-based cross-sectional seroprevalence study combined...

High rate of hepatitis C virus and human immunodeficiency virus false-positive results in serologic screening in sub-Saharan Africa: adverse impact on the blood supply.

False positivity in blood screening may cause unnecessary deferral of healthy donors and exacerbate blood shortages. An international multicenter study was conducted to estimate the frequency of HCV and HIV false seropositivity in seven African countries (Burundi, Cameroon, Democratic Republic of Congo, Madagascar, Mali, Mauritania, and Niger). Blood donations were tested for hepatitis C virus (HCV) and human immunodeficiency virus (HIV) with rapid detection tests (RDTs), third-generation enzyme immunoassays (EIAs), or fourth-generation EIAs. HCV (456/16,613 [2.74%]) and HIV (249/16,675 [1.49%]) reactive samples were then confirmed with antigen/antibody assays, immunoblots, and nucleic acid testing. Partial viral sequences were analyzed when possible. The HCV reactivity rate with RDTs was significantly lower than with EIAs (0.55% vs. 3.52%; p < 0.0001). The HIV reactivity rate with RDTs was lower than with third-generation EIAs (1.02% vs. 2.38%; p < 0.0001) but similar to a fourth-generation assay (1.09%). Only 16.0% (57/357) and 21.5% (38/177) of HCV and HIV initial reactive samples, respectively, were repeatedly reactive. HCV and HIV infections were confirmed in 13.2% and 13.7%, respectively, of repeated reactive donations. The predominant HCV genotype 2 and 4 strains in West and Central Africa showed high genetic variability. HIV-1 subtype CRF02_AG was most prevalent. High rates (>80%) of unconfirmed anti-HCV and anti-HIV reactivity observed in several sub-Saharan countries highlights the need for better testing and confirmatory strategies for donors screening in Africa. Without confirmatory testing, HCV and HIV prevalence in African blood donors has probably been overestimated.

HCV viraemia in anti-HCV-negative haemodialysis patients: Do we need HCV RNA detection test?

Hepatitis C virus (HCV) infection is still common among dialysis patients, but the natural history of HCV in this group is not completely understood. The KDIGO HCV guidelines of 2009 recommend that chronic haemodialysis patients be screened for HCV antibody upon admission to the dialysis clinic and every 6 months thereafter if susceptible to HCV infection. However, previous studies have shown the presence of HCV viraemia in anti-HCV-negative haemodialysis patients as up to 22%. To evaluate the presence of HCV viraemia, using HCV RNA detection, among anti-HCV-negative haemodialysis patients from a tertiary dialysis unit in Athens. We enrolled 41 anti-HCV-negative haemodialysis patients diagnosed with third-generation enzyme immunoassay. HCV viraemia was evaluated using a sensitive (cut-off: 12 IU/mL) reverse transcriptase polymerase chain reaction (COBAS AmpliPrep/TaqMan system) for HCV RNA. None of the 41 anti-HCV-negative haemodialysis patients were shown to be viraemic. Routine HCV RNA testing appears not to be necessary in anti-HCV-negative haemodialysis patients.

The accuracy of HIV rapid testing in integrated bio-behavioral surveys of men who have sex with men across 5 Provinces in South Africa.

We describe the accuracy of serial rapid HIV testing among men who have sex with men (MSM) in South Africa and discuss the implications for HIV testing and prevention.This was a cross-sectional survey conducted at five stand-alone facilities from five provinces.Demographic, behavioral, and clinical data were collected. Dried blood spots were obtained for HIV-related testing. Participants were offered rapid HIV testing using 2 rapid diagnostic tests (RDTs) in series. In the laboratory, reference HIV testing was conducted using a third-generation enzyme immunoassay (EIA) and a fourth-generation EIA as confirmatory. Accuracy, sensitivity, specificity, positive predictive value, negative predictive value, false-positive, and false-negative rates were determined.Between August 2015 and July 2016, 2503 participants were enrolled. Of these, 2343 were tested by RDT on site with a further 2137 (91.2%) having definitive results on both RDT and EIA. Sensitivity, specificity, positive predictive value, negative predictive value, false-positive rates, and false-negative rates were 92.6% [95% confidence interval (95% CI) 89.6–94.8], 99.4% (95% CI 98.9–99.7), 97.4% (95% CI 95.2–98.6), 98.3% (95% CI 97.6–98.8), 0.6% (95% CI 0.3–1.1), and 7.4% (95% CI 5.2–10.4), respectively. False negatives were similar to true positives with respect to virological profiles.Overall accuracy of the RDT algorithm was high, but sensitivity was lower than expected. Post-HIV test counseling should include discussions of possible false-negative results and the need for retesting among HIV negatives.

Current Diagnostic Methods for HIV

Detection of HIV infection is essential for diagnosis and monitoring of the infection. There are different types of diagnostic tools available that are based on detection of HIV-specific antibodies, viral antigen or nucleic acid. Sensitivities and specificities of assays utilized for HIV detection have improved. Newer HIV testing technologies such as third-generation enzyme immunoassay which detect HIV-specific IgG and IgM antibodies, fourth-generation enzyme immunoassay which detect both anti-HIV antibodies and HIV p24 antigen and nucleic acid based tests for HIV RNA have significantly decreased the window period. This review provides an overview of current technologies for the detection and monitoring of HIV infection and recent advances in the field of HIV diagnosis.

Hepatitis C in children with chronic kidney disease: A single-center, Egypt.

Prevalence of hepatitis C varies largely according to geographical distribution, and Egypt so far has the highest prevalence worldwide. The aim of this study was to evaluate hepatitis C infection in chronic kidney disease (CKD) children in our center with regard to its incidence and other morbidities. This is a cross-sectional study involving 50 children with CKD, not on dialysis. All patients underwent a thorough history taking including disease duration and mean duration of admission, clinical examination including blood pressure measurements, and routine laboratory examination such as hemoglobin level, serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), urea, and creatinine. The detection of anti-hepatitis C virus (HCV) antibodies was done in all patients based on the use of third-generation enzyme immunoassay (EIA) that detects antibodies directed against various HCV epitopes. Nine (18%) children were found to be hepatitis C positive and 41 were negative to hepatitis C. Infected cases were of older age group and had a longer duration of CKD, lower estimated glomerular filtration rate (eGFR), lower hemoglobin, higher ALT, higher serum urea, and creatinine. We conclude that 18% of children with CKDs have hepatitis C infection, and those with longer the duration of renal disease is more likely to be positive for HCV. Furthermore, HCV infection may predispose to higher deterioration of eGFR, lower hemoglobin level, and more days of admission. We recommend routine testing of HCV in all children with CKD.

Laboratory evaluation of the Chembio Dual Path Platform HIV-Syphilis Assay.

BackgroundUse of rapid diagnostic tests for HIV and syphilis has increased remarkably in the last decade. As new rapid diagnostic tests become available, there is a continuous need to assess their performance and operational characteristics prior to use in clinical settings.ObjectivesIn this study, we evaluated the performance of the Chembio Dual Path Platform (DPP®) HIV–Syphilis Assay to accurately diagnose HIV, syphilis, and HIV/syphilis co-infection.MethodIn 2013, 990 serum samples from the Georgia Public Health Laboratory in Atlanta, Georgia, United States were characterised for HIV and syphilis and used to evaluate the platform. HIV reference testing combined third-generation Enzyme Immunoassay and Western Blot, whereas reference testing for syphilis was conducted by the Treponema pallidum passive particle agglutination method and the TrepSure assay. We assessed the sensitivity and specificity of the DPP assay on this panel by comparing results with the HIV and syphilis reference testing algorithms.ResultsFor HIV, sensitivity was 99.8% and specificity was 98.4%; for syphilis, sensitivity was 98.8% and specificity was 99.4%. Of the 348 co-infected sera, 344 (98.9%) were detected accurately by the DPP assay, but 11 specimens had false-positive results (9 HIV and 2 syphilis) due to weak reactivity.ConclusionIn this evaluation, the Chembio DPP HIV–Syphilis Assay had high sensitivity and specificity for detecting both HIV and treponemal antibodies. Our results indicate that this assay could have a significant impact on the simultaneous screening of HIV and syphilis using a single test device for high-risk populations or pregnant women needing timely care and treatment.

Determination of HIV Status in African Adults With Discordant HIV Rapid Tests.

In resource-limited settings, HIV infection is often diagnosed using 2 rapid tests. If the results are discordant, a third tie-breaker test is often used to determine HIV status. This study characterized samples with discordant rapid tests and compared different testing strategies for determining HIV status in these cases. Samples were previously collected from 173 African adults in a population-based survey who had discordant rapid test results. Samples were classified as HIV positive or HIV negative using a rigorous testing algorithm that included two fourth-generation tests, a discriminatory test, and 2 HIV RNA tests. Tie-breaker tests were evaluated, including rapid tests (1 performed in-country), a third-generation enzyme immunoassay, and two fourth-generation tests. Selected samples were further characterized using additional assays. Twenty-nine samples (16.8%) were classified as HIV positive and 24 of those samples (82.8%) had undetectable HIV RNA. Antiretroviral drugs were detected in 1 sample. Sensitivity was 8.3%-43% for the rapid tests; 24.1% for the third-generation enzyme immunoassay; 95.8% and 96.6% for the fourth-generation tests. Specificity was lower for the fourth-generation tests than the other tests. Accuracy ranged from 79.5% to 91.3%. In this population-based survey, most HIV-infected adults with discordant rapid tests were virally suppressed without antiretroviral drugs. Use of individual assays as tie-breaker tests was not a reliable method for determining HIV status in these individuals. More extensive testing algorithms that use a fourth-generation screening test with a discriminatory test and HIV RNA test are preferable for determining HIV status in these cases.

Incidence of recent HCV infection among persons seeking voluntary counselling and testing for HIV and sexually transmitted infections in Taiwan

IntroductionThe incidence of recent hepatitis C virus infection (HCV) infection has been noted to be increasing among men who have sex with men (MSM), especially those with HIV infection, in several resource-rich settings. In Taiwan, the incidence of recent HCV infection increased from 0 in 1994–2000, 2.29 in 2001–2005 to 10.13 per 1000 person-years of follow-up (PYFU) in 2006–2010. In this study, we aimed to estimate the incidence rate of recent HCV infection among those individuals who sought voluntary counselling and testing (VCT) service at a University Hospital.MethodsBetween May 2006 and December 2013, 18,246 tests for HIV antibody were performed among 12,143 individuals at the VCT services. A total of 2157 clients without HIV or HCV infection at baseline were included for estimation of incidence rate of recent HCV infection. Antibodies to HCV were determined with a third-generation enzyme immunoassay. A nested case-control study with four matched controls without HCV seroconversion for one HCV seroconverter was conducted to investigate the factors associated with recent HCV infection. Phylogenetic analysis was performed among the HCV strains obtained from VCT clients and patients coinfected with HIV and HCV between 2006 and 2013.ResultsDuring the study period, 2157 clients received a total of 8260 tests. The HCV seroprevalence at baseline was 0.3%. Of the 2150 HCV-negative clients who contributed 5074.99 PYFU, 17 developed HCV seroconversion (incidence rate, 3.35 per 1000 PYFU; 95% CI, 1.76–4.94); the rate increased from 2.28 per 1000 PYFU (95% CI, 0.05–4.51) in 2006–2009, to 3.33 per 1000 PYFU (95% CI, 0.86–5.80) in 2010–2011, to 4.94 per 1000 PYFU (95% CI, 0.99–8.99) in 2012–2013. In case-control study, HCV seroconverters were more likely to have HIV-infected partners, recent syphilis and a Rapid Plasma Reagin (RPR) titre of 4 or greater. In multivariate analysis, having HIV-infected partners remained as the only independent associated factors with HCV seroconversion (AOR, 6.931; 95% CI, 1.064–45.163). Phylogenetic analysis revealed transmission pairs and clusters, with most clustered sequences derived from MSM.ConclusionsSimilar to the observation among HIV-infected patients who are not IDUs, increasing trends of recent HCV infection also occur among the individuals who sought VCT services in Taiwan. Having HIV-infected partners is independently associated with recent HCV seroconversion.

Sero-Prevalence of Hepatitis B and Hepatitis C Virue Co-Infection among Pregnant Women in Nigeria

This study was carried out to determine sero-prevalence of hepatitis B and hepatitis C virus co-infection among pregnant women. Viral hepatitis during pregnancy is associated with high risk of maternal complications; infections with Hepatitis B virus (HBV) or the Hepatitis C virus (HCV) are public health problems. Worldwide, there are about 350 million HBV carriers and 130 to 170 million people infected with HCV. The presence of HBV and HCV was determined using third-generation enzyme immunoassay (EIA), reactive samples were further confirmed using enzyme linked immune sorbent assay (ELISA) (Bio-Rad, France). Age group 26-30 and 31-35 had highest frequency of 240 (36.98%) and 206 (31.74%) respectively in HBV and HCV. Sero prevalence of HBV and HCV were 44 (6.78%) and 9 (1.39%) respectively. Prevalence of HBV and HCV co-infection was 1 (0.15%) in age group 31-35. Proper management of maternal hepatitis during the prenatal phase ensures better outcomes in the infant, therefore screening of pregnant women for hepatitis B and C virus are necessary in order to identify those neonates at risk of transmission.

Serum Antibody Titers Against Hepatitis C Virus and Postoperative Intrahepatic Recurrence of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the seventh most common cancer and the third leading cause of cancer deaths worldwide. Hepatitis C virus (HCV) infection is a major risk factor for HCC recurrence after curative resection. This study evaluated anti-HCV antibody (Ab) titer as a prognostic indicator of HCC recurrence after curative hepatic resection. A total of 82 patients with HCC (anti-HCV Ab positive and hepatitis B surface antigen negative) who underwent curative hepatic resection were evaluated. Anti-HCV Ab titers were measured using a third-generation enzyme immunoassay, and patients were divided into high (n = 41) and low (n = 41) titer groups to compare their clinicopathological characteristics and disease-free survival. Univariate and multivariate analyses were conducted to identify risk factors for early or late recurrence. Multivariate analysis showed that anti-HCV Ab titer and vascular invasion were independent prognostic factors of disease-free survival [odds ratio (OR) 1.9, p = 0.03, and OR 1.8, p = 0.04, respectively]. Subgroup analysis identified only vascular invasion as an independent prognostic factor for early recurrences that were considered residual intrahepatic metastases. Subgroup analysis identified anti-HCV Ab titer and fibrosis grade as independent prognostic factors of late recurrences that were considered to be metachronous multicentric liver carcinogenesis (OR 4.8, p = 0.04, and OR 5.2, p = 0.03, respectively). Anti-HCV Ab titer is a predictive factor for HCC recurrence, especially the risk of late recurrence due to multicentric carcinogenesis. Prevention of liver carcinogenesis after hepatic resection for HCC might be appropriate for patients with high anti-HCV Ab titers.

Rubella Antibody Status of Patients Attending a South-West London Antenatal Clinic, 2007–2012

Mass vaccination with the measles-mumps-rubella (MMR) vaccine for children aged 12–15 months was introduced in 1988; schoolgirl vaccination was discontinued in 1996 and replaced by a second dose of MMR for preschool children and post-partum vaccination of susceptible women identified through antenatal testing. In the UK, declining uptake rates due to concerns about the MMR vaccine, and increasing numbers of cases in some European countries where rubella surveillance and preconceptional vaccination are inadequate, coupled with poor uptake rates, has started to show in the number of rubella-susceptible patients presenting at antenatal clinics (ANCs). In this study, samples were collected in serum separator tubes at the West Middlesex University Hospital (WMUH) ANC and sent to the laboratory. Rubella status was determined using a third-generation rubella IgG enzyme immunoassay. Any negative results were retested and confirmed using an alternative method. The concentrations were expressed as iu/mL (World Health Organization [WHO] standard). Over a five-year period, the number of rubella-susceptible patients increased from 4.1% to 6.8% of the total number of specimens tested. The current population susceptibility levels seem to be influenced by a number of factors: the target population, age at vaccination and the level of coverage, and exposure to wild virus.

Targeting screening and social marketing to increase detection of acute HIV infection in men who have sex with men in Vancouver, British Columbia

Objectives:The contribution of acute HIV infection (AHI) to transmission is widely recognized, and increasing AHI diagnosis capacity can enhance HIV prevention through subsequent behavior change or intervention. We examined the impact of targeted pooled nucleic acid amplification testing (NAAT) and social marketing to increase AHI diagnosis among men who have sex with men (MSM) in Vancouver.Design:Observational study.Methods:We implemented pooled NAAT following negative third-generation enzyme immunoassay (EIA) testing for males above 18 years in six clinics accessed by MSM, accompanied by two social marketing campaigns developed by a community gay men's health organization. We compared test volume and diagnosis rates for pre-implementation (April 2006–March 2009) and post-implementation (April 2009–March 2012) periods. After implementation, we used linear regression to examine quarterly trends and calculated diagnostic yield.Results:After implementation, the AHI diagnosis rate significantly increased from 1.03 to 1.84 per 1000 tests, as did quarterly HIV test volumes and acute to non-acute diagnosis ratio. Of the 217 new HIV diagnoses after implementation, 54 (24.9%) were AHIs (25 detected by pooled NAAT only) for an increased diagnostic yield of 11.5%. The average number of prior negative HIV tests (past 2 years) increased significantly for newly diagnosed MSM at the six study clinics compared to other newly diagnosed MSM in British Columbia, per quarter.Conclusion:Targeted implementation of pooled NAAT at clinics accessed by MSM is effective in increasing AHI diagnoses compared to third-generation EIA testing. Social marketing campaigns accompanying pooled NAAT implementation may contribute to increasing AHI diagnoses and frequency of HIV testing.

Prevalence and risk factors of Hepatitis C virus infection in Brazil, 2005 through 2009: a cross-sectional study.

BackgroundHepatitis C chronic liver disease is a major cause of liver transplant in developed countries. This article reports the first nationwide population-based survey conducted to estimate the seroprevalence of HCV antibodies and associated risk factors in the urban population of Brazil.MethodsThe cross sectional study was conducted in all Brazilian macro-regions from 2005 to 2009, as a stratified multistage cluster sample of 19,503 inhabitants aged between 10 and 69 years, representing individuals living in all 26 State capitals and the Federal District. Hepatitis C antibodies were detected by a third-generation enzyme immunoassay. Seropositive individuals were retested by Polymerase Chain Reaction and genotyped. Adjusted prevalence was estimated by macro-regions. Potential risk factors associated with HCV infection were assessed by calculating the crude and adjusted odds ratios, 95% confidence intervals (95% CI) and p values. Population attributable risk was estimated for multiple factors using a case–control approach.ResultsThe overall weighted prevalence of hepatitis C antibodies was 1.38% (95% CI: 1.12%–1.64%). Prevalence of infection increased in older groups but was similar for both sexes. The multivariate model showed the following to be predictors of HCV infection: age, injected drug use (OR = 6.65), sniffed drug use (OR = 2.59), hospitalization (OR = 1.90), groups socially deprived by the lack of sewage disposal (OR = 2.53), and injection with glass syringe (OR = 1.52, with a borderline p value). The genotypes 1 (subtypes 1a, 1b), 2b and 3a were identified. The estimated population attributable risk for the ensemble of risk factors was 40%. Approximately 1.3 million individuals would be expected to be anti-HCV-positive in the country.ConclusionsThe large estimated absolute numbers of infected individuals reveals the burden of the disease in the near future, giving rise to costs for the health care system and society at large. The known risk factors explain less than 50% of the infected cases, limiting the prevention strategies. Our findings regarding risk behaviors associated with HCV infection showed that there is still room for improving strategies for reducing transmission among drug users and nosocomial infection, as well as a need for specific prevention and control strategies targeting individuals living in poverty.

Screening for Acute Human Immunodeficiency Virus Infection in Baltimore Public Testing Sites

Human immunodeficiency virus (HIV) RNA testing of pooled HIV antibody-negative specimens can identify acute HIV infection (AHI) and trigger interventions to reduce transmission during this highly infectious period. A Baltimore, MD program serving sexually transmitted disease clinics and other high-risk sites combined HIV testing by third-generation enzyme immunoassay (EIA) with RNA testing of pooled antibody-negative specimens. Laboratory and Disease Intervention Specialists' records were reviewed for program evaluation. A cost analysis was performed. In 22 months, we tested 60,695 specimens for HIV. Of these, 1766 (2.9%) tested positive by EIA. Pooled HIV RNA testing of 58,925 EIA-negative specimens detected 7 cases of AHI (0.01%). Reflex HIV RNA testing of EIA-reactive, Western blot-indeterminate specimens confirmed 4 additional AHI cases (total AHI, 0.02%). Contact tracing detected no additional previously unknown cases of HIV infection. The utility of pooled HIV RNA testing may be limited by advances in HIV testing technology that reduce the seronegative window period and by characteristics of the local HIV epidemic.

HEPATITIS C VIRUS INFECTION IN HEMODIALYSIS PATIENTS: COMPARISON OF THE SURABAYA DIALYSIS CENTER AND JUNTENDO UNIVERSITY HOSPITAL DIALYSIS CENTRE

Hepatitis C virus infection is highly prevalence in chronic hemodialysis (HD) patients. The present study will compare prevalence of HCV positive population in difference countries where there are great contrasts in and diversity of care available to patients who have end stage renal disease. All serum samples of the 100 patients were tested for HCV antibodies, using third-generation enzyme immunoassay. The prevalence of anti-HCV was correlated with a history of blood transfusion and with duration of hemodialysis. HCV prevalences were 88% of Surabaya group and 6% of Juntendo Group, respectively. In Surabaya Group, prevalence of HCV positive was high and the risk factors are not only those of the Juntendo Group, but also a combination of poor living conditions, frequent blood transfusions, and lack of adherence. Much needs to be studied about the role of universal screening and effective techniques for primary prevention in Surabaya Group

The seroprevalence of hepatitis C virus (HCV) among 559,890 first-time volunteer blood donors in China reflects regional heterogeneity in HCV prevalence and changes in blood donor recruitment models.

A decrease in the prevalence of hepatitis C virus antibody (anti-HCV) has been reported among voluntary blood donors in some regions of China. However, the prevalence of HCV among volunteer blood donors in other regions of China has not been reported. The aim of this study was to investigate the seroprevalence of HCV among 559,890 first-time volunteer blood donors recruited during 2004 through 2007 at the Guangzhou Blood Center, China. Anti-HCV was detected using two different third-generation enzyme immunoassay kits. HCV RNA was detected using reverse transcription-polymerase chain reaction (RT-PCR) targeting the 5'-untranslated region of HCV. Among 559,890 donors, 1877 (0.335%) were positive for anti-HCV. The anti-HCV+ rate was significantly higher in males than females (0.37% vs. 0.28%; p < 0.001) and significantly lower among donors living in Guangdong Province than donors who had migrated from other locations (0.30% vs. 0.40%; p < 0.001). Among the 1877 anti-HCV+ donors, 450 were randomly selected for HCV nucleic acid amplification by RT-PCR. Of these, 270 (60%) were HCV RNA+ and 180 (40%) were HCV RNA-. Many donors from outside Guangdong Province were migrant laborers from other areas in China, suggesting that there is regional heterogenicity in HCV prevalence within China. The overall anti-HCV+ rate reported here is among the lowest reported among blood donors in China reflecting the effect of the current recruitment of exclusively volunteer donors.

Poor performance of hepatitis C antibody tests in hospital patients in Uganda

Most hepatitis C testing in Uganda is performed using commercial rapid strip assays (RSA) to detect antibodies to hepatitis C virus (anti-HCV), rather than enzyme immunoassays (EIA). The prevalence of hepatitis C antibodies in a Ugandan hospital population was determined using both methods to test their accuracy using nucleic acid testing (NAT) as a reference. Sera from 380 consecutive hospitalized Ugandan patients were tested for anti-HCV using an RSA in Uganda, with subsequent automated third-generation EIA testing in the United States, followed by NAT. Recombinant immunoblot assays (RIBA) were used as a supplementary test to detect anti-HCV epitopes. Overall, anti-HCV was detected in 48/380 (13%) by one or both antibody tests. Anti-HCV was detected in 19 (5.0%) patients by RSA and in 33 (8.7%) patients by EIA; only four patients were anti-HCV positive by both methods. Fourteen of the 48 anti-HCV positive patients had detectable serum HCV RNA, 7 each by bDNA assay or by PCR. RSA detected only 7 of 14 HCV RNA positive sera. Of 29 RNA negative but anti-HCV positive patients tested by RIBA, only two were anti-HCV positive; 27 were anti-HCV negative or indeterminate. Anti-HCV testing by RSA and/or EIA was neither sensitive nor specific for detection of ongoing HCV infection in hospitalized Ugandan patients. Our findings underscore the importance of confirmatory nucleic acid testing, which, despite its increased cost, appears essential to manage African patients with HCV.

Improved detection of hepatitis C virus infection by transcription-mediated amplification technology in dialysis population

Background: Hepatitis C virus (HCV) infection remains common among patients undergoing maintenance dialysis and plays an adverse effect on survival in this population. Accurate detection of HCV viremia (HCV RNA) in dialysis patients requires a sensitive and specific diagnostic test. Methods: The Versant™ HCV RNA Qualitative Assay, based on transcription-mediated amplification (TMA) technique, was prospectively evaluated in 112 dialysis patients. Performance characteristics of the Versant HCV TMA Assay were evaluated in comparison to the Amplicor® 2.0 HCV test based on polymerase chain reaction (PCR) technique. In addition, anti-HCV serologic tests including third-generation enzyme immunoassay and Recombinant Immunoblot Assay were performed. Results: Of the 112 specimens tested, 29 were reactive by Versant HCV TMA Assay, yielding an overall prevalence of HCV viremia of 25.9%. The concordance between TMA and PCR techniques was excellent [91% (101/112)]. Eleven specimens (10%) were invalid or equivocal by PCR due to interference phenomena; all 11 specimens had valid TMA results (2 patients being TMA reactive and 9 nonreactive). Four specimens [3.6% (4/112)] that tested PCR-negative and HCV TMA nonreactive were anti-HCV seropositive, consistent with resolved HCV infection. In the group of seronegative samples, one was reactive by TMA Assay [1.25% (1/80)]. Conclusions: The HCV TMA technology seems a highly sensitive tool for detecting HCV RNA in the dialysis population, with no evidence of specimen interference. One EIA-negative but HCV-RNA-positive patient by Versant HCV TMA Assay was identified. Prospective clinical trials are under way to assess the clinical impact related to the use of HCV TMA technology in dialysis population.