Assessment of potential factors associated with the sensitivity and specificity of Sofia Influenza A+B Fluorescent Immunoassay in an ambulatory care setting

• Published in: PloS one 2022-05, Vol.17 (5), p.e0268279-e0268279
• Main Authors: Bell, Cristalyne, Goss, Maureen, Birstler, Jennifer, Temte, Emily, Chen, Guanhua, Shult, Peter, Reisdorf, Erik, Haupt, Thomas, Barlow, Shari, Temte, Jonathan
• Format: Article
• Language: English
• Subjects: Age; Ambulatory care; Ambulatory medical care; Biology and life sciences; Clinics; Confidence intervals; Data analysis; Disease control; Evaluation; Fever; Fluorescence; Health care; Illnesses; Immunization; Immunoassay; Influenza; Influenza A; Medical care; Medical laboratories; Medicine and Health Sciences; Patients; Physicians; Polymerase chain reaction; Prevention; Primary care; Quality management; Research and Analysis Methods; Seasons; Sensitivity analysis; Surveillance; Vaccination; Vaccines; Variables; Viruses
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0268279

Seasonal influenza leads to an increase in outpatient clinic visits. Timely, accurate, and affordable testing could facilitate improved treatment outcomes. Rapid influenza diagnostic tests (RIDTs) provide results in as little as 15 minutes and are relatively inexpensive, but have reduced sensitivity when compared to RT-PCR. The contributions of multiple factors related to test performance are not well defined for ambulatory care settings. We assessed clinical and laboratory factors that may affect the sensitivity and specificity of Sofia Influenza A+B Fluorescence Immunoassay. We performed a post-hoc assessment of surveillance data amassed over seven years from five primary care clinics. We analyzed 4,475 paired RIDT and RT-PCR results from specimens collected from patients presenting with respiratory symptoms and examined eleven potential factors with additional sub-categories that could affect RIDT sensitivity. In an unadjusted analysis, greater sensitivity was associated with the presence of an influenza-like illness (ILI), no other virus detected, no seasonal influenza vaccination, younger age, lower cycle threshold value, fewer days since illness onset, nasal discharge, stuffy nose, and fever. After adjustment, presence of an ILI, younger age, fewer days from onset, no co-detection, and presence of a nasal discharge maintained significance. Clinical and laboratory factors may affect RIDT sensitivity. Identifying potential factors during point-of-care testing could aid clinicians in appropriately interpreting negative influenza RIDT results.