Screening haemodialysis patients for hepatitis C in Vietnam: The inconsistency between common hepatitis C virus serological and virological tests

Abstract

Selecting the appropriate screening method and interval for the early detection of hepatitis C virus (HCV) infection in low-resourced haemodialysis settings is a challenge. The challenge occurs when patients are classified as HCV-RNA positive but negative to HCV-core antigen (HCV-coreAg), anti-HCV and genotyping tests. We aim to clarify the inconsistency between HCV-RNA, HCV-coreAg, anti-HCV and HCV genotyping tests in haemodialysis patients and determine the reliability of HCV-coreAg as a routine two-monthly screening strategy. Haemodialysis patients were tested every 2 months between 2012 and 2014 at the largest district haemodialysis unit in Ho Chi Minh City, Vietnam, for aminotransferases, anti-HCV antibodies, HCV-coreAg, HCV-RNA and HCV genotype. HCV-coreAg and anti-HCV results were tested against HCV-RNA for sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV). All 201 patients participated in the study. The HCV-coreAg test performed better than the anti-HCV test for sensitivity (100% vs 31%), NPV (100% vs 90%) and accuracy (100% vs 90%). The HCV-coreAg and anti-HCV tests performed no differently for specificity (100% and 98%, respectively) or PPV (100% and 73%, respectively). Kappa values for HCV-coreAg and anti-HCV tests were 1 and 0.39, respectively. Early detection of HCV for the purpose of infection prevention requires a high level of sensitivity and HCV-coreAg performed better in our chronic haemodialysis population as a two-monthly screening method than routine anti-HCV testing. HCV-coreAg test is less labour-intensive with a higher level of accuracy in patients with low viral loads making it cost effective for low-resourced settings. Repeating genotyping may be required in HCV-coreAg positive patients with a low viral load.

Laboratory Evaluation of Hepatitis C Virus Infection in Patients Undergoing Hemodialysis from North East India

“…This findings was in concordance with previous other study results. 10 The superiority of fourth-generation HCV (core Agantibody combined detection) assay-based studies over third-generation anti-HCV antibody detection is established in our research, as was found out by previous works. 13,31 Besides much better sensitivity and specificity, a 100% specificity vis-a-vis gold standard HCV RNA testing is noteworthy.…”

“…Our findings corroborate well with similar previous works. 10 Because genotype distribution can have a bearing on antibody-based test results, a kit covering (responding to) multiple genotypes is ideal for diagnostic purpose. 40,41 A Paris-based study found differing sensitivities of ELISA kits depending on HCV genotypes.…”

“…9 However, these antibodies are not detectable in the first 4-6 weeks after infection (window period) and may remain undetectable longer in patients undergoing hemodialysis. [10][11][12] A positive anti-HCV test can be due to a past cured infection and does not always mean a current disease. 11 To call it a current infection needs verification by molecular techniques (NAT [nucleic acid amplification test]) for the detection of HCV RNA.…”

Prevalence of hepatitis B and C virus infections in hemodialysis patients in Vietnam: A systematic review and meta‐analysis

“…[34][35][36][37] The move away from anti-HCV toward HCV-coreAg screening is based on the need for accuracy, with experts suggesting that, while the nucleic acid testing (NAT) technique is superior to anti-HCV, it should be replaced with HCV-coreAg for routine monitoring of chronic hemodialysis patients because HCV-coreAg is more cost-effective, less labor-intensive, and comparable for accuracy. Half (56%, 9/16) of the studies reported exclusively on hemodialysis patients, and the majority (15/16) of publications were based in well-equipped tertiary hospitals.…”

Updated Evidence on the Epidemiology of Hepatitis C Virus in Hemodialysis

“…The information on prevalence and incidence rates of HCV among patients on regular dialysis in the emerging world is limited, and the most important survey to date has been given by the Asia-Pacific Dialysis Registry ( n = 201,590), which found that the prevalence of positive anti-HCV serologic status ranged between 0.7% and 18.1% across 10 various areas and regions [ 6 ]. Numerous single-center surveys from emerging countries have been published in the last decade, and these have reported high prevalence and incidence rates ( Table 1 ) [ 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ].…”