Analysis of reactive HCV results detected by current blood screening strategy / 中国输血杂志

【Objective】 To assess the status of HCV infection by analyzing the results of anti-HCV reactive blood samples detected by the current blood testing strategy, and discuss the viability of classified management of reactive blood donors. 【Methods】 The anti-HCV reactive samples (dual ELISA and once NAT), from May 2017 to October 2018, were divided into three groups: samples both anti-HCV and HCV RNA reactive, sole HCV RNA reactive, and sole anti-HCV reactive, and all of them were confirmed by recombinant immunoblot assay (RIBA). The positive predictive value (PPV) between groups were compared. The sensitivity, specificity and PPV for each reagent under different screening threshold (screening threshold for routine detection, optimal screening threshold, and corresponding screening threshold of the highest PPV) were analyzed. The group with low PPV were stratified by ELISA S/CO values, and PPV by different screening threshold was compared. 【Results】 There were 939 reactive samples (0.49%, 937/191 627). Confirmed by RIBA, the positive rate of anti-HCV reactive samples was 10.67%(100/937). Two samples were sole HCV RNA reactive (0.001%). Both anti-HCV+ HCV RNA reactive samples were 6.71%(63/939), with the PPV of 96.83%(61/63). Sole anti-HCV reactive samples were 93.08(874/939), with the PPV of 4.46%(39/874), among which PPV by dual and one ELISA reagent were 18.72% and 0.15%, respectively, showing statistically significant difference (P<0.05). The PPV between different S/CO values was statistically significant (P<0.05). The optimal screening thresholds of anti-HCV reagent were 9.29 and 3.97, according to the ROC curve, with significant difference noticed in PPV by different screening threshold (P<0.05). PPV in the sole anti-HCV reactive group increased from 4.46% (the routine screening threshold) to 49.35%(the optimal screening threshold), and the difference was statistically significant (P<0.05). 【Conclusion】 The blood donors with both anti-HCV and HCV RNA reactive can be determined as HCV infection and need to be permanently deferred. The S/CO value of sole anti-HCV reactive samples was positively correlated with RIBA confirmation results, and the higher the S/CO value, the greater the chances of positive confirmation are. With the current blood screening strategy, the HCV infection status of sole anti-HCV reactive blood donors can be determined by establishing a screening threshold with high PPV or adding confirmatory test.

Indeterminate RIBA results were associated with the absence of hepatitis C virus RNA (HCV-RNA) in blood donors

Introduction: Hepatitis C virus (HCV) infection is diagnosed by the presence of antibodies and is supplemented by confirmatory testing methods, such as recombinant immunoblot assay (RIBA) and HCV-RNA detection. This study aimed to evaluate the efficacy of RIBA testing to diagnose HCV infection in blood donors positive for anti-HCV antibodies. Methods: A total of 102 subjects positive for anti-HCV determined by enzyme-linked immunosorbent assay (ELISA) at the Hematology and Hemotherapy Foundation of Bahia (HEMOBA) were later assessed with new samples using the Abbott Architect anti-HCV test (Abbott Diagnostics, Wiesbaden, Germany), the RIBA III test (Chiron RIBA HCV 3.0 SIA, Chiron Corp., Emeryville, CA, USA), the polymerase chain reaction (PCR; COBAS® AMPLICOR HCV Roche Diagnostics Corp., Indianapolis, IN, USA) and line probe assay (LiPA - Siemens, Tarrytown, NY, USA) genotyping for HCV diagnosis. Results: Of these new samples, 38.2% (39/102) were positive, 57.8% (59/102) were negative and 3.9% (4/102) were indeterminate for anti-HCV; HCV-RNA was detected in 22.5% (23/102) of the samples. RIBA results were positive in 58.1% (25/43), negative in 9.3% (4/43) and indeterminate in 32.6% (14/43) of the samples. The prevailing genotypes were 1 (78.3%, 18/23), 3 (17.4%, 4/23) and 2 (4.3%, 1/23). All 14 samples with indeterminate RIBA results had undetectable viral loads (detection limit ≤50 IU/mL). Of these samples, 71.4% (10/14) were reevaluated six months later. Eighty percent (8/10) of these samples remained indeterminate by RIBA, and 20% (2/10) were negative. Conclusions: In this study, individuals with indeterminate RIBA results had no detectable HCV-RNA. .

The Correlation between the S/CO Ratio of Anti-HCV ELISA, and the Results of the RIBA and RNA Test / 대한수혈학회지

BACKGROUND: Recombinant immunoblot assay (RIBA) or RNA test is considered to be a supplemental test for confirming a HCV infection. A correlation has been reported between the signal-to-cutoff (S/CO) ratios of a third generation HCV enzyme-linked immunosorbent assay (ELISA) and a confirmed HCV infection. This study examined the results of an evaluation of domestic anti-HCV EIA and immunoblot kit (RIBA) in Korean donors. METHODS: A total of 375,576 donor samples were tested for anti-HCV using the LG third generation HCV ELISA (LG HCD 3.0 TMB, LGphD, Korea) and HCV RNA by NAT (Biomerieux/Roche RT-PCR, 24 pool). The anti-HCV repeat reactive samples were further tested by third generation RIBA (LG HCD Confirm, LGphD, Korea). A positive result by either the nucleic acid amplification test (NAT) or RIBA was interpreted as a confirmed HCV infection. RESULTS: There were 506 out of the 375,576 donor samples (0.13%) that were anti-HCV repeat reactive (RR) by routine screening ELISA. The confirmed HCV prevalence in the donors was 0.01% (RIBA 42/375,570, RNA 36/375,570). 443 samples from the 506 repeat reactive samples in ELISA (87.6%) showed a S/CO ratio 3.6 (mean 4.40+/-0.80), compared with the negative group (mean 1.54+/-0.64). CONCLUSION: There was a good correlation between a high S/CO ratios and a confirmed HCV infection. In addition, samples showing a low S/CO ratio with an ID (Indeterminate) or negative RIBA result suggest a high probability of nonspecific reactivity in ELISA.

Confirmation of HCV Positivity for Indeterminate Donors in Anti-HCV Antibody Immunoblot Assay among Blood Donors / 대한수혈학회지

BACKGROUND: In Korean Red Cross, recombinant immunoblot assay (RIBA) has been used for the confirmatory test of HCV positive units since 1995. To certify the HCV infection in blood donors who showed the 'indeterminate result on the RIBA test, this study was performed. METHODS: Three enzyme immunoassay (EIA) kits (LG HCD 3.0, DONG-A HCV 3.0, and ORTHO HCV 3.0)and RNA detection method were employed to evaluate infection state of 135 samples of the 'indeterminate in the RIBA test. RESULTS: The 52.6% of the samples showed the same test results with three EIA kits. Fifteen samples (11.1%) were HCV RNA positive with RT-PCR-hybridization technique. Among 15 samples of HCV RNA positive, 13 (86.7%), 13 (86.7%), and 14(93.3%) of samples were positive in LG HCD 3.0, Ortho HCV 3.0 and Dong-A HCV 3.0 EIA, respectively. In the analysis of RIBA band reaction, HCV RNA positivity were correlated with core14, core518, and 897 antigen. However, among 64 samples which react with core antigen only, five samples (7.8%) were HCV RNA positive. CONCLUSION: Based on the results of the present study, it is recommend that the HCV RNA test be used as a method of confirmatory test in order to notify exact HCV positivity status to blood donor who showed indeterminate RIBA result.

Comparison between Different Methods and Reagents for Testing Anti-HCV in Blood Donors / 中国输血杂志

82 serum samples from the blood donors were comparatively tested by using different reagent kits and two methods (enzyme-linked immunosorbent assay, ELISA anl passive hemagglutination inhibition assay, PHA). The results are as follows: the positive rates of A1, A2 , A3 , A4-1 and B (containing mixed antigens) are 56.09%, 71.95%, 47.56%, 63.41% and 59.75% respectively; and the positive rates of A4-2 and A4-3 (containing single antigens) are 41.46% and 62.19% respectively. The results of testing 8 of all the serum samples by four-gene-recombinent immunoblot assay (RIBA) confirmed that the results of A1, A2, A3, A4-1 and A4-3 were consistent with them. The 76th sample with positive result when tested by RIBA had a negative result when tested by RIBA, while the 82th sample with negative result when tested by RIBA had posi tive one when tested by B. It is suggested that reagent kits made in China left much to be desired in antigen-matching, compactness and cut-off value determining, though they could screen out most of the donors with positive anti-HCV results.