MIKROBIYOLOJI BULTENI, cilt.43, ss.103-114, 2009 (SCI İndekslerine Giren Dergi)
External quality assessment (EQA) has been playing an increasingly important role in the implementation of nucleic acid amplification techniques (PCR) for clinical diagnosis. In this study, the results of HBV-DNA quantification and HCV-RNA detection tests evaluated by United Kingdom National External Quality Assessment Scheme for Microbiology (NEQAS) were analysed and the performance of our laboratory was evaluated. Between April 2006-January 2008, in four different distribution panels including 16 freeze-dried serum and six plasma specimens for HBV-DNA and HCV-RNA testing, respectively, were received. Viral nucleic acids were extracted by magnetic particle technology (NucliSENS-easyMAG, bioMerieux, Boxtel, Holland). HBV-DNA and HCV-RNA tests were performed by Fluorion HBV quantitative v2.0 and Fluorion HCV quantitative v2.1 (Iontek AS, Istanbul, Turkey) kits in real-time PCR (iCycler IQ v3.0a - BioRad Laboratories, Hercules, CA, USA) platform. The performance scores of all the quantification tests of HBV-DNA were 2 (completely correct result) and a strong correlation (r = 0.987) between the quantitative HBV data and the target values was found by linear regression analysis. The NEQAS scores of HCV-RNA testing, except for a false negative result (since the viral load in this specimen was very low -79 IU/ml- it was not scored by NEQAS), were 2 in all specimens. The evaluation of the data revealed 100% detection in HBV-DNA and 83.3% detection in HCV-RNA. In conclusion, the results of this study showed high accuracy of HBV quantification in the samples of HBV infected patients under antiviral therapy. However, the analytical sensitivity of HCV-RNA quantitative kit should be improved for the purpose of reliable HCV-RNA results. External quality control panels are important tools for monitoring the quality of diagnostic laboratory tests. Therefore, PCR laboratories should always have EQA in routine procedures.