Rapid tests for respiratory viruses show high specificity, wide range of sensitivity

The sensitivity of rapid tests for detecting respiratory viruses varied widely but showed high specificity, according to a recently published meta-analysis.

Overall, researchers added that even though new tests seemed more sensitive, “high-quality evaluations of these tests are lacking.

“Acute respiratory tract infections are a leading cause of morbidity worldwide. There is a clear trend towards point-of-care testing and the number and quality of rapid diagnostic tests for respiratory viruses has rapidly increased,” Andrea H.L. Bruning, MD, of the department of infectious diseases at Emma Children’s Hospital Academic Medical Center, University of Amsterdam, and colleagues wrote. “For clinicians, it is important to be aware of the diagnostic accuracy of the different rapid viral tests, the factors that affect their accuracies and test performances in daily practice. Previous systematic reviews addressing the diagnostic accuracy of respiratory tests evaluated either only one respiratory virus, ie, influenza or [respiratory syncytial virus], were conducted in specific populations.”

The researchers used the Medline and EMBASE databases for studies that evaluated rapid diagnosis tests compared with PCR tests, reviewing 179 studies of 50 different tests: 134 evaluating rapid tests for influenza, 32 for respiratory syncytial virus and 13 for other viruses. Bruning and colleagues performed a quantitative meta-analysis of the studies using the bivariate random effects model.

The sensitivity of rapid influenza tests ranged from 4.4% to 100%, Bruning and colleagues reported, with a summary estimate of 61.1% (95% CI, 53.3-68.3). The summary estimate for specificity was 98.9% (95% CI, 98.4-99.3).

Rapid tests for respiratory syncytial virus showed sensitivity ranging from 41.5% to 88.6%, the researchers wrote, with an overall sensitivity of 75.3% (95% CI, 72.6-77.8) and specificity of 98.7% (95% CI, 97.3-99.4). Bruning and colleagues did not perform meta-analyses for adenovirus, parainfluenza or hMPV because of the small number of studies focusing on those diseases.

The researchers noted that in influenza tests, sensitivity was lower for detecting H1N1 (54%; 95% CI, 47.6-60.3) compared with other subtypes. Influenza tests were also significantly less accurate when performed on adults compared with a mixed population or children (34.1%; 95% CI, 14-54.1). The tests for respiratory syncytial virus did not vary with patient age (P = .20).

“In the current era of emerging novel respiratory viruses, there is a growing need for rapid, sensitive and specific identification of viral pathogens to allow effective prompt antimicrobial therapy, decrease extra diagnostic testing and implement pathogen-specific infection control measures,” the researchers wrote. “Although some studies have already evaluated the impact of rapid diagnostics on patient management, randomized controlled trials are needed to assess the clinical relevance of rapid tests in terms of clinically relevant outcomes, such as antibiotic use, length of hospital stay and cost-efficiency.” – by Andy Polhamus

Disclosure: The researchers report no relevant financial disclosures.