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.

The Role of the Signal-to-Cutoff Ratio in Automated Anti-HCV Chemiluminescent Immunoassays by Referring to the Nucleic Acid Amplification Test and the Recombinant Immunoblot Assay

BACKGROUND: Following discontinuation of the recombinant immunoblot assay (RIBA), the only available supplementary test for the detection of hepatitis C virus (HCV) is the nucleic acid amplification test (NAAT). However, the NAAT does not adequately detect past HCV. Consequently, it is hard to distinguish between past HCV infection and biological false positivity with an anti-HCV result alone. We assessed the diagnostic performance of two immunoassays: the ARCHITECT anti-HCV chemiluminescent microparticle immunoassay (CMIA; Abbott Diagnostics, Wiesbaden, Germany) and the Access HCV Ab PLUS chemiluminescent immunoassay (CIA; Bio-Rad, Marnes-la-Coquette, France). We also explored an optimized algorithm to determine the anti-HCV results. METHODS: We tested 126,919 patients and 44,556 individuals who underwent a medical checkup. RIBA and NAAT were conducted for samples that tested anti-HCV-positive using CMIA and CIA. We assessed the optimal signal-to-cutoff (S/CO) ratio in HCV-positive samples. RESULTS: In total, 1,035 blood samples tested anti-HCV-positive. Of these, RIBA was positive in 512, indeterminate in 160, and negative in 363 samples. One hundred sixty-five samples were NAAT-positive. Diagnostic sensitivity and positive predictive value (PPV) were 96.7% and 52.1%, respectively, for CMIA, and 94.7% and 72.3%, respectively, for CIA. The optimal S/CO ratio was 5.2 for CMIA and 2.6 for CIA at 95% PPV. In total, 286 samples tested positive in CMIA and 444 in CIA, while 443 samples tested positive in both assays. CONCLUSIONS: It is hard to determine anti-HCV positivity based on the S/CO ratio alone. However, this study elucidated the role of the S/CO ratio by using the NAAT and RIBA.

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.

A case: control study on the risk factors of hepatitis C virus infection among Koreans

In order to identify the risk factors for hepatitis C virus (HCV) infections, a case-control study was conducted from September 1993 to April 1994. HCV infection was confirmed by the second generation of recombinant immunoblot assay. Sixty-four cases and 128 controls matched for age and sex with a 1:2 ratio of cases to controls were enrolled. Exposure data were obtained from all participants by self-administered questionnaire and the odds ratios of possible risk factors of HCV infection analysed. Sixty-four cases consisted of forty-two patients with chronic hepatitis, nine with cirrhosis, one with hepatocellular carcinoma, and twelve with normal liver function. History of acute hepatitis (OR 3.9) and transfusion (OR 2.4) were associated with an increased risk of HCV infection. Operation, acupuncture, endoscopy, tooth extraction, tattooing, ear piercing, needle sharing and family history of hepatitis were not associated with an increased risk of HCV infection. In conclusion, transfusion remains the major route of transmission of HCV in Korea.