Evaluation of PCR assays in presence of antibody to thermostable DNA polymerases for detection of microbial agents: avoiding false negative results for specimen containing low-titer agent.

The serial low-titer specimens of Influenza A virus and Adeno virus type 7 were tested for the presence of virus specific genes by PCR based on Tth DNA polymerase and by that based on Taq DNA polymerase, in the absence and presence of antibody to the respective DNA polymerases. Increased product DNA synthesis and higher sensitivity of detection were observed in the presence of antibody compared to those in the absence of antibody. 10- to 100- fold lower titer specimen of Influenza A virus and 10-fold lower titer specimen of Adeno virus could be detected in the presence of antibody than those detected in the absence of antibody to the appropriate DNA polymerase, in a PCR.