Model for Interpreting Discordant SARS-CoV-2 Diagnostic Test Results

Area of Science:

• Infectious Diseases
• Epidemiology
• Diagnostic Accuracy

Background:

• Discordant results between rapid antigen tests and nucleic acid tests for SARS-CoV-2 pose a challenge in clinical decision-making.
• Accurate interpretation of conflicting diagnostic results is crucial for effective public health strategies and patient management during the COVID-19 pandemic.

Purpose of the Study:

• To develop and validate a predictive model for interpreting discordant SARS-CoV-2 test results.
• To estimate the probability of infection in individuals with a positive rapid antigen test followed by a negative nucleic acid test.

Main Methods:

• Development of a statistical model to analyze SARS-CoV-2 test result discordance.
• Utilized data from patients in the United States between March 2020 and May 2022.
• Estimated the likelihood of infection based on sequential positive rapid antigen and negative nucleic acid test results.

Main Results:

• A model was devised to interpret discordant SARS-CoV-2 test results.
• For patients in the U.S. (March 2020-May 2022), a positive rapid antigen test followed by a negative nucleic acid test yielded an estimated 15.4% probability of infection (95% CI 0.6%-56.7%).

Conclusions:

• The study provides a quantitative estimate for the probability of SARS-CoV-2 infection given specific discordant test results.
• Findings suggest that a negative nucleic acid test following a positive rapid antigen test significantly reduces the likelihood of a true infection.