[Clinical assessment of Monolisa HCV Ag-Ab ULTRA (Bio-Rad) in a general hospital]

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

INTRODUCTION

Subjects undergoing hemodialysis have enhanced vulnerability to hepatitis C virus (HCV) infection due to invasive procedures and poor infection control practices. Early detection and treatment are essential to prevent cross-infection and mortality/morbidity. However, common use anti-HCV antibody tests lack the necessary accuracy, and alternative tests (e.g. core antigen detection kits) which are available need to be examined as a viable alternative.

METHOD

A total of 270 continuous serum samples were collected from patients undergoing dialysis within 15 months of study period. Sequentially, multiple tests were performed - immunochromatography-based rapid test, third-generation ELISA i.e. (anti-HCV antibody detection), fourth-generation ELISA (HCV antigen-antibody combined detection assay), and HCV RNA quantitative real time polymerase chain reaction (qPCR) assay. Diagnostic parameters of serological kits were compared in terms of sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy, and so on. Statistical Package for the Social Sciences was used.

RESULTS

HCV-combined core antigen-antibody assays performed better than other serological assays in reference to the gold standard HCV RNA. This fourth-generation assay yielded a Kappa value of 0.947 compared with the value of 0.747 and 0.619 for anti-HCV ELISA and rapid detection test. Other parameters such as sensitivity, specificity, PPV, NPV, and so on were also better for fourth-generation ELISA compared with third-generation ELISA and other serological assays. HCV RNA was negative in 7.3% of anti-HCV-positive patients and was detected in 11.4% of anti-HCV ELISA-negative patients. In about 1.6% of HCV RNA-positive cases, fourth-generation ELISA was negative and had low HCV viral load (650 IU/ml and below). Fourth generation ELISA detected additional 7.4% HCV positive cases (compared to third generation kits) and upon cost effective analyis, additional cost to be bear for the better detection (by fourth generation kit) was found to be only INR 27 per 1% increased case detection.

CONCLUSION

In resource scant setup, screening and follow-up of patients undergoing hemodialysis can be performed by fourth-generation HCV ELISA (antigen-antibody combined assay) instead of the current practice of anti-HCV antibody ELISA. Better yield in detection rate will compensate for slight addition to costs.

Diagnostic Performance of an Immunoassay for Simultaneous Detection of Hcv Core Antigen and Antibodies among Haemodialysis Patients

Nosocomial transmission of HCV is a concern in haemodialysis (HD) units worldwide. Diagnosis of HCV infection among dialysis patients is currently based on the detection of anti HCV antibodies by ELISA, and is confirmed by HCV RNA. The average window period between HCV infection and seroconversion with new generations of HCV antibody tests remains approximately 70 days with more prolonged period among dialysis patients. In this study we assessed the diagnostic performance of an immunoassay designed for simultaneous detection of anti HCV antibodies and core antigen in one step in comparison to qualitative RT-PCR and anti HCV antibodies detection test among Egyptian haemodialysis patients. The studied patients were 39 chronic renal failure patients on maintenance haemodialysis. The results obtained in the present study revealed HCV infection of 56.4%. Combined Ag/Ab test detected 3 out of the 4 anti-HCV negative viraemic patients who were in the window period. The sensitivity, specificity and accuracy of the test were higher than that of anti HCV antibodies detection test (95.45%, 94.1% and 94.87% versus 81.8%, 88.23% and 84.6%) and they were raised to 100% on combining its positivity with liver enzymes elevation results. Therefore, this simple combined Ag/Ab test can be applied for early detection of HCV infection during window period among HD patients as an alternative to HCV RNA detection.

Comparison of monolisa HCV Ag/Ab ULTRA with two anti-HCV assays for the detection of HCV infection in hospital setting

In this study, we compared the performance of three serological assays (Monolisa HCV Ag/Ab ULTRA, Innotest HCV Ab IV enzyme immunoassay--EIA, and Ortho HCV 3.0 enzyme-linked immunosorbent assay--ELISA) for the detection of HCV infection. Ninety plasma samples were collected, representing 63 samples from groups at risk for acquiring HCV infection and 27 HCV RNA-positive samples. The results of Ortho HCV 3.0 ELISA, Innotest HCV Ab IV, and Monolisa HCV Ag/Ab ULTRA were fully concordant for 27 HCV RNA-positive samples. Ortho HCV 3.0 ELISA test and Innotest HCV Ab IV also gave the same results for risk groups, while three samples were found to be reactive by Monolisa HCV Ag/Ab ULTRA and were consequently found negative for HCV RNA. As two of the solely Monolisa HCV Ag/Ab ULTRA-positive samples were also hepatitis B s antigen (HBsAg)-positive, neutralization of HBsAg was performed but no arguments for the HBsAg interference were observed. In conclusion, the non-specific reactive signal was observed, in three samples using Monolisa HCV Ag/Ab ULTRA, to be negative by other serological assays, and observed to be negative in an HCV RNA assessment, a result that could not be attributed to the interference with HBsAg. In the context of diagnostic testing, no test for various HCV genotypes was observed to be superior to any other.

Simultaneous detection of hepatitis C virus core antigen and antibodies in Saudi drug users using a novel assay

Drug users and particularly, injecting drug users, are at increased risk for infection with hepatitis C virus (HCV). The aims of the study were to simultaneously detect HCV core antigen and specific antibodies in sera from Saudi drug users using the new HCV combination assay and to compare this data with HCV core antigen, anti-HCV antibodies and HCV RNA data from the same patients. A total of 297 patients who are followed up or admitted to a drug rehabilitation hospital over a period of 3 years were included in this study. Samples were analyzed using the new HCV Ag/Ab combination assay (Meurex), HCV core Ag assay, HCV antibodies and with the HCV RNA assay. Out of the 297 samples from Saudi drug users, 111 samples (37.4%) have detectable HCV core Ag, 112 samples (37.7%) have detectable HCV antibodies, 118 have detectable HCV RNA, and 116 samples were positive by the HCV Ag/Ab combination assay (39.1%). Out of the 116 samples, HCV core Ag was detected in 110 samples (94.8%), HCV antibodies were detected in 111 (95.7%) samples and HCV RNA was detected in 114 samples (98.3%). In the control group (n = 305), only 2 (0.66%) blood donor were positive by HCV antibodies assay, HCV RNA assay as well as HCV Ag/Ab combination assay. The new HCV Ag/Ab combination assay may well improve the overall quality of diagnosis of HCV infection especially in high risk population such as drug users that necessitates rigorous testing.