Comparison of methods for extraction of nucleic acid from hemolytic serum for PCR amplification of hepatitis B virus DNA sequences.

The sensitivity of PCR for the amplification of target nucleic acid sequences in clinical diagnostics may often be reduced due to the presence of inhibitory factors. Hemolytic serum contains a number of PCR inhibitors, one of which is hemin. In this study we have found that conventional methods of DNA extraction were not sufficient for the removal of PCR-inhibitory compounds in hemolytic serum. We have therefore compared the efficiency of several commercial and noncommercial methods of nucleic acid purification from hemolytic serum samples prior to PCR amplification. Separation with the QIAamp HCV kit, dialysis with Millipore filters, and bovine serum albumin absorption were all found to be suitable extraction methods for eliminating inhibitors from hemolytic serum for PCR amplification. Using these methods we were able to detect very low levels of hepatitis B virus DNA in hemolytic serum.