FRESH BLOOD SAMPLES VERSUS ARCHIVED SAMPLES IN HEPATITIS C VIRUS SCREENING: A COMPARATIVE STUDY

Abstract

A low prevalence of Hepatitis C virus infection ranging from 0.1% to  0.9% has continuously been reported in the Kenyan population. Several studies have however concentrated on special groups like Intravenous Drug Users (IDUs) and blood bank samples, with no major study carried out in the general population. This study aimed at testing and comparing results of fresh and archived Hepatitis C infected samples obtained both from patients in Kenya and in Germany. Fresh and archived samples in Kenya were obtained from patients attending the liver clinic at the Kenyatta National Hospital and those stored at the Kenya Medical Research Institute (KEMRI), respectively. Fresh and archived samples from Germany were obtained from patients attending HCV treatment at the two main Ludwig Maximillian University hospitals in Germany and those  stored at the Max von Pettenkofer Institute (MvPI)- Munich Germany, respectively. Freshly obtained samples were subjected to serological assays by Enzyme Linked Immunosorbent assay platforms (Ortho HCV 3.0 ELISA test system with an enhanced SAVe and AxSYM ELISA test system,  for German samples and Murex ELISA test system, for Kenyan Samples)  commonly used in each individual country before subjecting all the samples to a similar nested PCR diagnosis. All the archived samples had also been subjected to PCR diagnosis and confirmed positive at least once in the course of their storage.   A total of 25 and 50 samples from Kenya and Germany, respectively, were tested and compared.   All the 50 (100%) ELISA positive German samples were again confirmed PCR positive  in the standardized PCR diagnostic system, whereas Kenyan samples realized varied results. Despite 100% (4 out of 4) detection by PCR on fresh samples, no detection, 0% (0 out of 21), was realized on the archived samples. These archived Kenyan samples could not also be detected by the available antibody based rapid detection kits. Based on the results realized with archived samples, whose conditions are deemed similar to the blood bank conditions in Kenya, this study asserts that although stored blood bank samples have continuously been used to estimate the prevalence of Hepatitis C infection in Kenya, this parameter may not be appropriate in estimating the true prevalence of this infection in the general population. Therefore, the study concludes and recommends the need to screen and determine the true prevalence of the infection using samples from the general population, since together with Hepatitis B, Hepatitis C infection are emerging as a major point of focus in blood transfusion screening in Kenya. The study further recommends that together with serological assays, Nucleic Acid based Techniques (NAT) should be employed in screening all freshly obtained blood before storage.