Background and objectives: Nucleic acid testing was introduced at our blood transfusion service in order to reduce the diagnostic preseroconversion window for transfusion relevant viruses.
Materials and methods: Up to 96 donor samples were pooled overnight by two Tecan Genesis RSP 150 pipettors. Pools were centrifuged at 48,000 g for one hour to enrich viruses. Viral nucleic acids were extracted from centrifugation pellets using modified Qiagen viral RNA kit. HIV and HBV sequences were amplified by in house TaqMan PCR's with patented primers and probes for HBV. HCV PCR was performed by Roche Amplicor V2.0. "Nadis" software was developed for pooling, resolving positive pools and data communication with main frame computer.
Results: PCR testing was introduced in January 1997 for HCV HBV and HIV-1 for all plasma products and for labile components at the 21st of April 1997. Throughput increased from 2000 to 4000 samples per day. PCR testing is done in parallel to serological testing and products are released eight hours after pooling is completed. Until January 2000, 1,078,940 donations have been tested in 13,274 pools. A total of seven PCR only positives were identified (3 HCV, 3 HBV, 1 HIV).
Conclusion: The yield of PCR testing for transfusion relevant viruses confirms theoretical estimates on the residual risk of antibody screening.