Cochrane for Clinicians

Putting Evidence into Practice

Rapid Point-of-Care Antigen and Molecular Tests for Diagnosis of SARS-CoV-2 Infection

 

Am Fam Physician. 2021 Jul ;104(1):29-30.

Author disclosure: No relevant financial affiliations.

Clinical Question

What are the sensitivity and specificity of point-of-care antigen and molecular-based tests for detecting SARS-CoV-2?

Evidence-Based Answer

SARS-CoV-2 antigen tests have an average sensitivity of 68.9% (95% CI, 61.8% to 75.1%) and an average specificity of 99.6% (95% CI, 99.0% to 99.8%). Accuracy depends on symptom status, time from symptom onset, and test brand. The Standard Q COVID-19 antigen test (SD Biosensor) has a sensitivity of 85.8% (95% CI, 80.5% to 89.8%) and specificity of 99.2% (95% CI, 98.2% to 99.6%).1 (Strength of Recommendation [SOR]: B, based on inconsistent or limited-quality patient-oriented evidence.)

SARS-CoV-2 rapid molecular tests have an average sensitivity and specificity of 95.1% (95% CI, 90.5% to 97.6%) and 98.8% (95% CI, 98.3% to 99.2%), respectively. The Xpert Xpress SARS-CoV-2 test (Cepheid) has a sensitivity and specificity of 100% (95% CI, 88.1% to 100%) and 97.2% (95% CI, 89.4% to 99.3%), respectively.1 (SOR: B, based on inconsistent or limited-quality patient-oriented evidence.)

Practice Pointers

Rapid and accurate point-of-care SARS-CoV-2 tests are valuable tools to slow the spread of the virus and safely return people to work and school. To be widely useful, these tests need to be portable and easy to perform, require less operator expertise and only a minimal amount of extra equipment, be inexpensive, and provide results in less than two hours. The authors of this Cochrane review looked at the evidence for SARS-CoV-2 tests meeting these criteria.1

This review has been updated once already and includes studies released through November 2020.1 It involves 64 reports with 78 studies of antigen or molecular tests suitable for point-of-care testing with 24,087 samples, 7,415 of which were confirmed by traditional polymerase chain reaction (PCR) testing to have SARS-CoV-2. Most studies were conducted in Europe and North America.

Included studies evaluated 16 commercial antigen tests, most of which targeted the nucleocapsid protein. Overall, the average sensitivity was 68.9% (95% CI, 61.8% to 75.1%) and the average specificity was 99.6% (95% CI, 99.0% to 99.8%; 21,614 samples; 6,136 confirmed SARS-CoV-2 cases). Accuracy was impacted by symptom status, time from symptom onset, and test brand. On average, sensitivity was greater in those who had symptoms (72%; 95% CI, 63.7% to 79.0%; 37 studies, 15,530 samples, 4,410 cases) than in those without symptoms

Author disclosure: No relevant financial affiliations.

References

1. Dinnes J, Deeks JJ, Berhane S, et al.; Cochrane COVID-19 Diagnostic Test Accuracy Group. Rapid, point-of-care antigen and molecular-based tests for diagnosis of SARS-CoV-2 infection. Cochrane Database Syst Rev. 2021;(3):CD013705.

2. Centers for Disease Control and Prevention. SARS-CoV-2 (COVID-19) fact sheet: guidance–proposed use of point-of-care testing platforms for SARS-CoV-2 (COVID-19). March 2021. Accessed June 1, 2021. https://www.cdc.gov/coronavirus/2019-ncov/downloads/OASH-COVID-19-guidance-testing-platforms.pdf

These are summaries of reviews from the Cochrane Library.

This series is coordinated by Corey D. Fogleman, MD, assistant medical editor.

A collection of Cochrane for Clinicians published in AFP is available at https://www.aafp.org/afp/cochrane.

 

 

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