Diagnostic accuracy of various hepatitis c rapid tests against elisa in detection of hepatitis c infection.

Abstract

INTRODUCTION: HCV is one of the leading causes of liver disease in the world with over 71 million people infected and in Uganda, HCV sero-prevalence estimates range from 0.0% to 14.6%. It is predominantly a blood borne virus transmitted mainly through blood transfusions and injecting drug use. Hepatitis C infection ranges from acute liver disease that is 6 months from the time of infection or can be chronic when the infection lasts longer than 6 months. According to WHO, around 30% (15–45%) of infected persons spontaneously clear the virus within 6 months of infection without any treatment. The remaining 70% (55–85%) of persons will develop chronic HCV infection. Of those with chronic HCV infection, the risk of cirrhosis ranges between 15% and 30% within 20 years hence developing liver disease. In diagnosis of Hepatitis C, WHO recommends serological tests for antibody detection and those positive for HCV antibodies are tested with RNA PCR to confirm active infection. False positives have however been reported with most serological tests that are used in HCV screening. In Uganda RDTs are commonly used for the anti Hepc Ab detection however, most of the commercially used RDTs on the Ugandan market have not been fully evaluated for their technical performance. Thus there is limited data on the diagnostic accuracy of the different RDTs and blood bank screening tests in the Ugandan setting. AIM: The overall aim of this study was to evaluate the diagnostic accuracy of RDTs for HCV Ab detection against ELISA. METHODS: Whole blood from blood donors in Soroti was collected, processed and tested for Hepatitis C antibodies with 4 different RDTs, Acro Biotech, Onsite CTK Biotech, One-step Diagnostic Automation and Standard Q SD Biosensor as well as the blood bank Abbot Architect Chemilluminescent Microparticle Immunoassay method against the Abnova ELISA as gold standard. All antibody positive samples based on RDT/ELISA or Abbot Architect were then subjected to the HepC RNA Real time reverse transcriptase PCR to determine the proportion of antibody positive patients who actually had active HepC infection. RESULTS: Of the 300 samples tested with the four different RDTs and the ABNOVA ELISA, a total of 167 samples were positive. The RDTs Acro Biotech, Onsite CTK Biotech, One-step Diagnostic Automation and Standard Q SD Biosensor as well as the blood bank Architect method gave 50, 48, 30, 39 and 47 antibody positives, respectively. The Abnova ELISA gave a total of 15 antibody positives. The sensitivity of RDTs Acro Biotech, Onsite CTK Biotech, One-step Diagnostic Automation and vii Standard Q SD Biosensor as well as the blood bank Architect machine were 66.7%, 66.7%, 60.0%, 46.7% and 33.3% and their corresponding specificity were 86.0%, 86.7%, 92.6%, 88.8%, and 85.3% respectively. Based on the RNA PCR testing, only 3 samples out of the 167 turned positive, and all the 3 were Ab positive based on the Abnova ELISA but only one had been picked by the Blood Bank Architect and Fortress ELISA. CONCLUSION: In summary this study demonstrated that all the RDTs evaluated generally had low sensitivity. The One-step Diagnostic Automation Hepatitis C RDT showed the least number of false positives of all Anti-HCV RDTs evaluated on the Ugandan Market. Most of the positive results reported by the blood bank Antibody tests were falsely positive. From this study it reveals that the available evaluated HCV RDTs on the Ugandan market may not be suitable HCV screening programs in Uganda since none of the RDT Antibody tests evaluated reached the WHO recommended sensitivity of ≥ 98% and specificity of ≥ 97%.