Evaluation of a new NASBA assay for the qualitative detection of hepatitis C virus based on the NucliSens® Basic Kit reagents

Background: Direct detection of HCV RNA by nucleic acid amplification methods is an essential tool in the diagnosis of HCV infections. In-house developed methods based on reverse transcribed polymerase chain reaction (RT-PCR) are widely used but they are laborious and usually lack the standardization required by clinical laboratories. Objectives: To evaluate the sensitivity and the clinical performance of an HCV specific nucleic acid sequence based amplification (NASBA) assay based on the commercially available, NucliSens® Basic Kit (bioMérieux) reagents. Study design: The analytical sensitivity of the Basic Kit-based HCV assay (BK-HCV) was determined using dilutions of the First World Health Organization International Standard for HCV RNA. The performance of the BK-HCV was evaluated at two study sites in comparison with in-house RT-nested PCR (RT-nPCR) by testing a total of 77 plasma specimens. Additional HCV laboratory tests such as Amplicor® HCV v2.0 (Roche Diagnostics) and genotype were also included in the comparative analysis. Results: The sensitivity of the BK-HCV was 100–150 IU/ml HCV RNA (85–100% hit rate). When evaluating the clinical performance, we found 96–100% correlation between BK-HCV and RT-nPCR, and 85–91% correlation between BK-HCV and Amplicor®. The level of efficiency of the BK-HCV for detecting prevalent HCV genotypes was equal to in house RT-nPCR and Amplicor®. Conclusions: The BK-HCV offers adequate sensitivity for diagnostic purposes and equivalent clinical performance to in-house RT-nPCR assays. The BK-HCV could become a suitable alternative to the in-house amplification methods, providing standardized reagents and procedures, plus rapid results to clinical laboratories.