Comparison of Rapid Antigen Detection Test with Reverse Transcription Polymerase Chain Reaction in Highly Suspected COVID-19 Patients.

Abstract

Objective: To compare Rapid Antigen Test (RAT) with Reverse Transcription Polymerase Chain Reaction (RT-PCR) in highly suspected COVID-19 patients and to determine its diagnostic parameters.

Study design: Hospital-based, descriptive/observational study. Place and Duration of the Study: Department of Medicine/COVID Complex, Medical Teaching Institution/Lady Reading Hospital, Peshawar, Khyber Pakhtunkhwa, Pakistan, from October 2021 to April 2022.

Methodology: A total of 300 highly suspected cases of COVID-19 of either gender admitted in the COVID Complex of the hospital, were included. Data from the patients, including RAT and RT-PCR for COVID-19, were collected retrospectively. RT-PCR was used as the reference test and compared with RAT. Diagnostic statistics of RAT, with their respective 95% confidence intervals were calculated for RAT in diagnosing COVID-19, with significance at p ≤0.05.

Results: Among the 300 patients, 137 (45.7%) were males and 163 (54.3%) were females. The mean age was 56.80 ± 13.72 years. On screening, 138 (46%) patients tested positive and 162 (54%) were negative by RAT; whereas 213 (71%) tested positive and 87 (29%) were negative on RT-PCR. The sensitivity and specificity of RAT were 54.5% (95% CI: 47.52%-61.28%) and 74.7% (95% CI: 64.25%-83.42%), respectively. Positive predicted value was 84.1% (95% CI: 78.26%-88.53%) and negative predictive value was 40.1% (95% CI: 35.63%-44.79%). The positive likelihood ratio was 2.15 (95% CI: 1.47-3.15). The negative likelihood-ratio was 0.61(95% CI: 0.50-0.74). The overall accuracy was 60.33% (95% CI: 54.55%-65.91%).

Conclusion: There was a low sensitivity and specificity of the RAT for COVID-19, with an overall accuracy of 60.33%, compared with RT-PCR.

Key words: COVID-19, Rapid Antigen Test, Sensitivity, Specificity, RT-PCR.