Table 3.

NAAT and Antigen Test Differences to Consider When Planning for Diagnostic or Screening Use [20,30].

	Nucleic Acid Amplification Test (NAATs)	Antigen Tests
Analyte Detected	Diagnose current infection	Diagnose current infection
Specimen Type(s)	Nasal, Nasopharyngeal, Oropharyngeal, Sputum, Saliva	Nasal, Nasopharyngeal, Breath
Sensitivity (for accuracy)	Laboratory tests: generally high Point-of-Care tests: moderate-to-high	Generally moderate-to-high at peak viral load. More accurate if symptomatic
Specificity	High	High
Authorized for Use at the Point-of-Care	Most are not	Most are
Turnaround Time	Most are 1–3 days Some rapid tests in 15 min	Most are 15–30 min
Cost per Test	Moderate (~$75–$100/test)	Low (~$5–$50/test)
Advantages	Most sensitive test available Short turnaround time for NAAT Point-of-Care tests (rare) Usually does not need to be repeated to confirm results	Short turnaround time (~15 min) Allows for rapid identification of infected people, thus preventing further virus transmission in the community, workplace, etc. Comparable performance to NAATs for diagnosis in symptomatic persons and whether a culturable virus is present or not
Disadvantages	Longer turnaround time for lab-based tests (1–3 days) Higher cost per test A positive NAAT diagnostic test should not be repeated within 90 days in case detectable RNA is still present after risk of transmission has passed	Less sensitive (more false negative results) compared to NAATs, especially among asymptomatic people and with some variants May need to be repeated to confirm results (any negative test on a symptomatic person should be confirmed with a PCR or NAAT test (CDC, 2022)