Validation of new real-time polymerase chain reaction assays for detection of hepatitis A virus RNA and parvovirus B19 DNA

BACKGROUNDTo meet European guidelines for plasma for fractionation, plasma fractionators have implemented parvovirus B19 (B19V) and hepatitis A virus (HAV) nucleic acid test (NAT) screening on test pools. In this study we evaluate recently developed in-house NAT assays for B19V DNA and HAV RNA. The B19V NAT was designed to target two different regions of the B19V genome. STUDY DESIGN AND METHODSThe B19V DNA and HAV RNA tests were validated according to commonly used guidelines. The performance of the B19V and HAV assays was evaluated during routine screening of more than 2 x 10(6) donations. RESULTSThe 95% lower limit of detection (LLD) of the HAV NAT was 1.34 IU/mL. The 95% LLD for B19V was 39.1 IU/mL for the NS1 region and 76.9 IU/mL for the VP2 region. The B19V test showed good accuracy, precision, robustness, and no cross-contamination was observed. Both assays detected B19V Genotypes 1 to 3 and HAV Genotypes I to III. During routine screening 103 donations showed B19V DNA loads of more than 1.25 x 10(6) IU/mL and one donation was reactive in the HAV NAT. CONCLUSIONThe dual-target B19V polymerase chain reaction (PCR) showed good accuracy (<0.1 log IU/mL) at the crucial concentration of 10 IU/mu L for the NS1 and the VP2 region of the B19V genome and detected all known genotypes with similar sensitivity for each genotype. In addition, the dual target format reduces the chance that molecular variants of B19V are wrongly quantified. The HAV RNA assay showed high sensitivity for Genotypes I to III. Both new PCR assays have been successfully introduced for plasma screening in test pools of 480 or 96 donations.