A sensitive PCR method for detecting HCV RNA in plasma pools, blood products, and single donations

Although current manufacturing processes appear to efficiently inactivate hepatitis C virus (HCV), it is possible that contaminated blood products may result from failure of some stage during manufacture or from virus overload of plasma pools used for preparation of products. While antibody screening probably removes the majority of HCV positive donations, some donations which are antibody-negative but HCV positive may be included in pools. The HCV RNA content of plasma pools from paid and voluntary donors was investigated by polymerase chain reaction (PCR). A sensitive PCR method using a single pair of primers from the 5' non-coding region of the HCV genome and a "hot-start" was established and shown to be as sensitive as the more conventional nested PCR (which uses two pairs of primers). The majority of pools from paid donors (prescreening) were HCV RNA positive, while all pools from voluntary donors were both antibody and RNA negative. Intravenous immunoglobulins prepared from contaminated pools were RNA negative despite having high antibody levels, indicating satisfactory clearance of the virus during manufacture. The virus load of the pools was at least a thousand-fold lower than that of single donations, possibly as a result of treatment during the production of the pools or the presence of factors in pools which reduce the sensitivity of some part of the PCR assay. The HCV content of a plasma donation was determined as 3.6 x 10(6) genomes/ml by an end point dilution method. Thus a simple and sensitive PCR assay was established for detecting HCV RNA in plasma pools and blood products.