Performance of direct immunofluorescence assay for the detection of human metapneumovirus under clinical laboratory settings

Human metapneumovirus (hMPV) is an emergent human respiratory pathogen. This study aimed to evaluate the performance of direct immunofluorescence (DIF) to detect hMPV in a clinical laboratory setting. Nasopharyngeal aspirate samples (448) of children and adults with respiratory illness were used to detect hMPV by using DIF and real time quantitative reverse transcription-polymerase chain reaction (qRT-PCR) assays. In all, 36 (8%) samples were positive by DIF and 94 (21%) were positive by qRT-PCR. Direct immunofluorescence specificity was 99% and sensitivity was 38%. DIF is not very sensitive under clinical laboratory settings.