Evaluation of real-time RT-PCR compared with conventional RT-PCR for detecting human metapneumovirus RNA from clinical specimens.

Human metapneumovirus (hMPV) is an etiologic agent of respiratory tract infections. In this study, we compared the sensitivity and specificity of real-time reverse transcription (RT)-polymerase chain reaction (PCR), conventional RT-PCR, and nested PCR in detecting hMPV genes. A total of 146 clinical specimens from 143 patients who showed acute respiratory tract infection symptoms were tested by real-time RT-PCR, conventional RT-PCR, and nested PCR targeting for the fusion gene. We detected hMPV RNA from 14 (9.6%) clinical specimens (real-time RT-PCR, 8; conventional RT-PCR, 5; and nested PCR, 13). When conventional RT-PCR was the reference standard, the sensitivity and specificity of real-time RT-PCR were 100 and 97.9%, respectively. When nested PCR was the standard, the sensitivity and specificity of real-time RT-PCR were 53.8 and 99.2%, respectively. Therefore, real-time RT-PCR was more sensitive than conventional RT-PCR but less so than nested PCR. Phylogenetic analysis showed that the real-time RT-PCR detected four genetic sublineages of hMPV. These results taken together indicate that real-time RT-PCR is an efficient method for detecting four genetic sublineages of hMPV from clinical specimens.