An interesting research paper published by Leber and others July 13th 2021 discusses this issue. Testing for COVID-19 with PCR is considered gold standard. Again this may result in delayed detection of disease.
Antigen detection via lateral flow testing is much faster and amenable to population-wide testing strategies.
This study assesses the diagnostic accuracy of lateral flow testing compared to PCR on the same primary care patients in Austria.
Patients with mild to moderate flu-like symptoms attending a general practice network in an Austrian district from October 22nd to November 30th 2020 received a clinical assessment including lateral flow test.
All suspected COVID-19 cases obtained an additional RT-PCR were divided into two groups:
- Group 1 true reactive suspected cases with reactive lateral flow testing and positive PCR.
- Group 2 false non-reactive suspected cases with a nonreactive lateral flow test but positive PCR.
Of the 2,562 symptomatic patients, 1,037 were suspected of COVID-19 and 826 79.7% patients tested PCR positive.
Amongst patients with positive PCR 788/826 tested lateral flow test reactive Group 1 and 38, 4.6% non-reactive Group 2.
Overall sensitivity was, 95.4%, specificity 89.1%, positive predictive value 97.3% and negative predictive value 82.5%.
Reactive lateral flow testing positive PCR were positively correlated.
Reactive lateral flow testing was negatively correlated with CT value and pre-test symptom duration while CT value is positively correlated with pre-test symptom duration.
This study showed that lateral flow testing is accurate alternative to PCR testing in primary care.
It is noted however the importance of administering the lateral flow test properly combined with clinical assessment in symptomatic patients.
LGP, THE LEADING LONDON DOCTORS’ CLINIC PROVIDES A FULL COVID-19 TESTING SERVICE
- Fast track PCR with results available within the four hours
- 5 Day Test for Release
- Fit to Fly
- Day 2, Day 5 and Day 8 Covid Testing
- Lateral flow antigen service
- Antibody Testing
Dr Paul Ettlinger
BM, DRCOG, FRCGP, FRIPH, DOccMed