Abstract:

Objective

To explore the result comparison using enzyme-linked immunosorbent assay (ELISA) to detect anti-hepatitis C virus antibody (anti-HCV) between two different laboratories and to provide basis for results mutual accreditation.

Methods

A total of 180 serum samples were recruited from the First Affiliated Hospital of Xinjiang Medical University from September 2014 to November 2014 in this study to estimate the precision between two different instruments through testing high, medium, and low concentrations in accordance with EP12-A2 files from the American association of Clinical Laboratory Standards Institute (CLSI). The domestic addcare ELISA 1100 full autokinetic enzyme analysis system(addcare ELISA 1100) was used to test HCV antibody under randomized blind method in different labs;recombinant immunoblot assay (RIBA) and polymerase chain reaction (PCR) were carried out to provide a evidence of true positive for HCV antibody tests. Further, we used receiver operating characteristic (ROC)curves to identify the optimal cut-off values, and compared the coincidence rate of HCV antibody tests,estimated the comparability of test results.

Results

The intra variation for Wantai and Kehua reagents were 5.0%, 8.1%, 9.8%, and 5.2%, 8.3%, 9.7%; the inter variation were 7.9%, 12.3%, 14.7%, and 8.0%, 12.7%,14.5%, respectively. A total of 78 samples were positive, 86 were negative, and uncertain results of 16 samples were found in 180 by the gold method. The optimal S/CO threshold values for Wantai and Kehua were 5.04 and 2.44 by drawing ROC with the positive predictive rate of 95% or higher; positive coincidence rate was 96%, negative coincidence rate was 95%, and total coincidence rate was 96%, without significant difference between the two labs (P>0.05).

Conclusions

The test results have a good comparability and recognition between the two laboratories. The negative samples with higher values and weakly positive specimens near the S/CO threshold values should be determined by the confirmed test to diagnose patients with HCV, which could provide the basis for the early diagnosis and treatment.

Key words: Hepatitis C antibody, enzyme-linked immunosorbent assay, Recombinant immunoblot assay, Coincidence rate