Rapid Laboratory Diagnostics during the Winter Respiratory Virus Season

During the winter season, the testing of respiratory specimens (i.e., for the identification of influenza viruses, respiratory syncytial viruses, parainfluenza viruses, and/or adenoviruses) remains a major initiative in the clinical virology laboratory. Such testing is often critical to the care and management of immunocompromised patients, infants, and young children, as well as elderly (3, 5, 6).

Liolios et al. (8) confirm the recognized analytical superiority of nucleic acid testing compared to conventional cell cultures and direct specimen testing or immunofluorescence technology. As Liolios and colleagues suggested, respiratory virus testing utilizing their multiplex reverse transcriptase (RT)-PCR protocol, “is able to provide rapid” results with “turnaround times of 24 to 36 h.” Many pediatric emergency room physicians, nursing home health care professionals, and infectious disease specialists would, however, take exception to the Australian workers’ definition of rapid respiratory virus diagnostics as appropriate to the clinical setting.

During the winter respiratory virus season, specifically in the hospital setting, virology laboratory personnel are under enormous pressure to meet specimen turnaround times; it is often requested that a verbal or computer report be delivered within 1 h or less for on-site patients or perhaps 2 to 3 h for those patients at off-site medical facilities (S. M. Lipson, personal observation). Rapid diagnostic testing, as defined in this commentary, is important for dividing patients into cohorts, for administration of antiviral drugs among the seriously ill, and for better antibiotic stewardship (2, 3, 4, 10, 13).

The study by Liolios and colleagues is of quality technical merit (8). In this laboratorian’s experience, however, the recommendation by Dr. Liolios et al. fails to meet specimen turnaround time demands made by the aforementioned physician groups during the winter respiratory virus season.

Regional and core medical center virology laboratories and commercial facilities are in continual competition for many of the same accounts. There is a continued effort, accordingly, to reduce specimen turnaround times in order to retain a competitive edge. To achieve this goal, many laboratory administrators direct their facilities to utilize rapid and simple-to-perform assays, rather than more-tedious but more-sensitive assays (2, 8, 9). The impetus to rapid respiratory viral diagnostics is reflected by the widespread use of the numerous enzyme immunoassay kits with detection times shorter than 15 min currently flooding the marketplace (1, 9).

The discipline of clinical virology is changing rapidly, and real-time testing is clearly the direction for the new millennium. Respiratory virus testing utilizing real-time nucleic acid amplification technologies is slowly being introduced to the clinical virology community (12). The technical study by Liolios et al., however, although capable of detecting seven respiratory virus types, fails to address the overwhelming practical issue of real-time (and simple-to-perform) laboratory viral diagnostics (8, 9). The described multiplex RT-PCR indeed serves as a valid epidemiological tool, but the assay’s 24- to 36-h turnaround time to the detection of respiratory viruses severely limits its routine application in the clinical setting. Until real-time multiplex nucleic acid testing becomes a reality, direct specimen testing along with immunofluorescence technology is likely to remain, in general, the most efficacious rapid (i.e., detection time of <1 h), sensitive, and specific methodology for the multiplex detection and identification of respiratory viruses in clinical specimens during the winter season (4, 7, 9, 11).