A study today in BMJ Open involving the Japan Professional Football League suggests that frequent COVID-19 rapid antigen testing (RAT) can better detect positive SARS-CoV-2 Omicron infections than infrequent polymerase chain reaction (PCR) testing, despite the latter's higher sensitivity.
Researchers from Osaka University compared the sensitivity of COVID-19 RATs with that of PCR tests among 1,759 soccer players and 1,864 staff members.
RATs and PCR tests were conducted twice weekly on the same day, "making this data set uniquely useful to assess the comparative sensitivity of these tests," senior author Seiya Imoto, PhD, of the University of Tokyo, said in an Osaka University news release. A total of 35,393 RATs were performed. Additional voluntary antigen and PCR testing were conducted in clubs with infected players.
10% positive on both rapid, PCR tests
The team analyzed 656 RAT and PCR results collected from Jan 12 to Mar 2, 2022. Sixty-five tests were positive on both RAT and PCR, 38 were negative on RAT and positive on PCR, 1 was positive on RAT and negative on PCR, and 552 were negative on both.
RAT sensitivity was 0.63, and specificity was 0.998. Sensitivity didn't vary significantly by interval between symptom onset and testing, symptom status, or vaccination status.
Sensitivity is the probability that a test correctly identifies all positive cases; the higher the sensitivity, the lower the likelihood of false-negative results. Specificity is the ability to identify those who don't have a condition; the higher the specificity, the lower the risk of false-positive results.
The results, the authors said, suggest that, as with previous variants, frequent RAT testing for Omicron outperforms infrequent PCR testing. While RATs require a larger volume of virus for a true positive result than PCR tests, they are cheaper and generate results quickly.