Comparison of Real-Time PCR Assays with Fluorescent-Antibody Assays for Diagnosis of Respiratory Virus Infections in Children

TLDR

The study aimed to demonstrate that real‑time PCR improves diagnosis of viral respiratory infections in children. The authors compared conventional fluorescent‑antibody assays to real‑time PCR for detecting RSV, FluA, PIV1‑3, MPV, and AdV in 1,138 pediatric respiratory specimens collected over one year. Real‑time PCR identified viruses in 53.4% of specimens versus 38.3% by fluorescent‑antibody, showing significantly higher sensitivity—especially for parainfluenza and adenovirus—and detected additional viruses in samples where fluorescent‑antibody results were negative or inadequate.

Abstract

ABSTRACT Conventional fluorescent-antibody (FA) methods were compared to real-time PCR assays for detection of respiratory syncytial virus (RSV), influenza virus type A (FluA), parainfluenza virus types 1, 2, and 3 (PIV1, PIV2, and PIV3), human metapneumovirus (MPV), and adenovirus (AdV) in 1,138 specimens from children with respiratory illnesses collected over a 1-year period. At least one virus was detected in 436 (38.3%) specimens by FA and in 608 (53.4%) specimens by PCR ( P < 0.001). Specimen quality was inadequate for FA in 52 (4.6%) specimens; 13 of these (25%) were positive by PCR. In contrast, 18 (1.6%) specimens could not be analyzed by PCR; 1 of these was positive by FA. The number of specimens positive only by PCR among specimens positive by PCR and/or FA was 18 (7.0%) of 257 for RSV, 18 (13.4%) of 134 for FluA, 25 (64.1%) of 39 for PIV1, 8 (88.9%) of 9 for PIV2, 17 (30.1%) of 55 for PIV3, and 101 (76.5%) of 132 for AdV. MPV was detected in 6.6% of all specimens and in 9.5% of the 702 specimens negative by FA. The mean number of virus copies per milliliter in specimens positive by both PCR and FA was significantly higher, at 6.7 × 10 7 , than that in specimens positive only by PCR, at 4.1 × 10 4 ( P < 0.001). The PCR assays were significantly more sensitive than FA assays for detecting respiratory viruses, especially parainfluenza virus and adenovirus. Use of real-time PCR to identify viral respiratory pathogens in children will lead to improved diagnosis of respiratory illness.