GAT Testing: Added Value?

Abstract

Genome amplification technologies (GAT) provide a new approach for testing blood donations for viruses. After extraction of nucleic acids, the target sequence is hybridised by virus specific probes. Various amplification processes of the target (PCR, NASBA, TMA, SDA) or of the probe signal (bDNA, LCR), as well as several detection methods allow for a very high sensitivity. The more general term “nucleic acid amplification testing” (NAT) tends to be preferred to GAT considering the array of technical approaches. In the last 5 years, advances in extraction, amplification and detection steps led to better mastered techniques and commercially available tests kits. Thus, from the technical standpoint, viral genomic screening (VGS), appears to be a realistic potential addition to the present tests carried out on blood donations. As it is targeted at the essence of viruses, nucleic acids, VGS is a direct test in contrast with antibody screening presently used for HCV or HIV. In the latter case, VGS is expected to better reduce the window period than HIV p24 antigen screening. Therefore VGS appears to be the direction of improvement in the detection of window period donations.