Table 1.

Comparison of Methods of Laboratory Diagnosis of SARS-CoV-2

Testing Method	Preferred Specimen	Sensitivity	Specificity	Turnover Time	Utility	Limitations
Laboratory-based RT-PCR	Paired nasopharyngeal and throat swab in ambulatory patients; bronchoalveolar lavage in patients on mechanical ventilator	71%–98%∗	98–100%	6–18 hours	Current infection with virus; viral detection in acute illness; gold standard diagnostic test	Sophisticated equipment; longer turnaround time; need for efficient cold-chain transport system and storage of specimen; trained laboratory staff
CBNAAT	Paired nasopharyngeal and throat swab in ambulatory patients; bronchoalveolar lavage in patients on mechanical ventilator	96%–100% compared with RT-PCR†	96%–100% compared with RT-PCR†	30–45 minutes	On-demand, rapid, easy-to-use diagnostic test	Need for continuous power supply; expensive in India; cartridge waste disposal required; trained laboratory staff
TrueNAT	Paired nasopharyngeal and throat swab in ambulatory patients; bronchoalveolar lavage in patients on mechanical ventilator	85%–92% compared with culture in studies of tuberculosis‡	98%–99% compared with culture in studies of tuberculosis‡	35–50 minutes	Point of care, portable, cost effective rapid diagnostic test	Low throughput (tests a maximum of 4 samples at a time)
Rapid Antigen Test	Nasopharyngeal swab	23.9%–93.9% compared with RT-PCR	~100% compared with RT-PCR	15–30 minutes	Useful as a screening test in health care settings in conjunction with nucleic acid tests (e.g., before emergency surgery while nucleic acid test results are awaited)	Cannot be used as a standalone diagnostic or screening test; limited sensitivity
Antibody-based test	Blood	40%–86% during second week of illness§	78%–100%	1–12 hours	Serosurveys; past infection; return-to-work decision; plasma donation	Not useful as a diagnostic test; potential for cross-reactivity

SARS-CoV-2, severe acute respiratory syndrome coronavirus 2; RT-PCR, reverse transcription-polymerase chain reaction; CB-NAAT, cartridge-based nucleic acid amplification test.

^∗Performance depends on the type of specimen.

^†Data regarding performance of cartridge-based tests for detection of SARS-CoV-2 are still scarce.

^‡No studies have been conducted regarding the performance of TrueNAT for SARS-CoV-2 detection.

^§Performance is time-dependent.