NAT update: where are we today?

The US blood supply has been tested for HIV-1 and HCV using Nucleic Acid Amplification Testing (NAT) of small pools since early in 1999. Since the implementation of NAT under an investigational new drug (IND) application, the results for yield and false positivity have been amazingly consistent for greater than two years of testing even among multiple programmes using two different test methodologies and manufacturers: Gen-Probe/Chiron transcription-mediated amplification (TMA) and Roche PCR. All programmes in the US and Canada use NAT as a criterion for cellular as well as frozen product release. The focus of this manuscript is to provide an update of the programmes in the US and Canada, provide data in support of p24 antigen replacement by HIV-1 NAT, and discuss the projections of residual risk of HIV, HCV and HBV following NAT and the associated cost/benefit.