Charakterystyka testu cobas® DPX przeznaczonego do badania dawców krwi na obecność DNA parwowirusa B19 (B19V) i RNA HAV przy użyciu analizatora cobas® 6800 oraz aparatu cobas p 680 firmy Roche

IntroductionThe cobas DPX test for use on the cobas 6800 system, is real-time PCR test for the identification and quantitation of human parvovirus B19 (B19V) DNA and the detection of hepatitis A virus (HAV) RNA in human plasma. Optional component to the cobas 6800 system is the cobas p 680 instrument that creates pools from individual samples. AimTo evaluate the performance of cobas® DPX test and to demonstrate its ability to detect HAV and polymorphic forms of B19V during plasma testing. Sensitivity, correct identification of reactive donations and risk of false positive results was estimated.Material and methodThe analytical sensitivity of cobas® DPX test was assessed by testing dilutions of the WHO B19V Genotype 1-3 Reference Panels (09/110) and IS WHO RNA HAV (00/562) dilution panel. Six dilutions of each B19 panel were tested ranging from 31.6 IU/mL to 0.1 IU /mL of genotype 1, 2, 3 and six dilutions of RNA HAV panel ranging from 10-0,03 IU/ml (24 replicates/dilution). Detection and identification of reactive donations tested in minipools were evaluated by testing 767 negative and 1 high DNA B19V reactive donations in 8 pools. The 95% limits of detection [LOD] (95% confidence range) of the cobas® DPX test for DNA B19V were respectively: genotype 1 - 8.70 IU/mL (4.92-21.69), genotype 2 - 37.80 IU/ml (22.24 – 93.65), genotype 3 - 29.84 IU/ml (19.04-65.60) and for RNA HAV were: 0.82 IU/ml (0.49 -1.96). Results of the cobas® DPX test from samples analyzed in minipools were 100% concordant with the expected results. No false reactive or invalid results was observed during donation screening. ConclusionThe cobas® DPX test on the cobas 6800 system allows to identify donations infected with HAV and genotypes 1-3 of B19V that could result contamination of plasma production pools with HAV and B19V beyond acceptable level (u003e104 IU/mL, according to recommendations). There was no significant risk of false results during evaluation procedure.