Caution in evaluation of removal of virus by filtration: Misinterpretation due to detection of viral genome fragments by PCR

► Q-PCR assays may be of use to evaluate viral removal by filtration, instead of infectivity assays. ► However, it should be noted that the result obtained by Q-PCR might be underestimated for the removal of the manufacturing process when only degraded fragments of viral genome are targets for a Q-PCR assay. ► Hence the results of Q-PCR should be interpreted cautiously. ► Careful design of primers is needed to eliminate amplification by Q-PCR from viral DNA fragments.