At-Home Influenza Test as Accurate as Diagnostic Testing

At-home rapid diagnostic tests (RDTs) may be as accurate at detecting influenza as rapid testing in clinical settings, according to results of a comparative accuracy study.

Included were individuals with acute respiratory illness symptoms from the greater Seattle region in Washington, United States from February 2020 to March 2020. All participants completed the RDT as well as collected a reference sample that was sent to a laboratory for quantitative reverse-transcription polymerase chain reaction testing.

Of the 605 total participants who completed the study, 14.4% (n = 87) tested positive for influenza by the laboratory reference test. When compared with the reference test, the overall sensitivity of the RDT was 61% (95% CI, 50%-71%), and the overall specificity was 95% (95% CI, 41%-74%).

The sensitivity of the RDT was lower among individuals who tested more than 72 hours after symptom onset. In individuals with symptom onset of 72 hours or less, the sensitivity was 63% (95% CI, 48%-76%0 and specificity was 94% (95% CI, 91%-97%). In individuals who tested more than 72 hours after symptom onset, the sensitivity was 58% (95%, 41%-74%) and specificity was 96% (95% CI, 93%-98%). However, the RDT did not have higher sensitivity or specificity among individuals with more severe illness.

The quantities of endogenous marker gene ribonuclease P did not differ between reference standard positive and negative groups, age groups, or influenza subtypes. There was a negative correlation between viral load on reference swabs and symptom onset.

“The sensitivity and specificity of the self-test were comparable with those of influenza RDTs used in clinical settings,” researchers concluded. “False-negative self-test results were more common when the test was used after 72 hours of symptom onset but were not related to inadequate swab collection or severity of illness. Therefore, the deployment of home tests may provide a valuable tool to support the management of influenza and other respiratory infections.”

—Leigh Precopio

Reference:

Geyer RE, Kotnik JH, Lyon V, et al. Diagnostic accuracy of an at-home, rapid self-test for influenza: prospective comparative accuracy study. JMIR Public Health Surveill. 2022;8(2):e28268. doi:10.2196/28268