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.