Table 1.

Causes of a negative RT-PCR COVID-19 test result (nasopharyngeal or oropharyngeal swabbing)

RESULT	CAUSE
a. True negative	Properly conducted test in a patient with another viral infection or condition
b. False negative	Delayed testing of patient beyond the time when the virus is in the upper airway
c. False negative	Sampling for virus has been inadequate (a throat swab is less effective than a nasopharyngeal swab)
d. False negative	Transport of specimen to laboratory is faulty (delays, integrity of specimen, etc)
e. False negative	Insensitivity inherent in the testing platform (eg, manufacturer shortcomings)

COVID-19—coronavirus disease 2019, RT-PCR—reverse transcriptase–polymerase chain reaction.