Table 2. Interpretation of test resultsa .
aDerived from Uyeki et al.[7]
NAAT: nucleic acid amplification test; RIDT: rapid influenza diagnostic test; RT-PCR: reverse transcription polymerase chain reaction.
| Influenza prevalent season | Non-influenza prevalent season | |||
|---|---|---|---|---|
| RIDT | Negative results:
Negative predictive values are low
● Possible false negative, primarily if the test is performed four days after the onset of disease ● A negative result cannot be used as a basis for not initiating treatment if antiviral therapy is clinically indicated ● Confirmation with a more sensitive test is required |
Positive results:
Positive predictive values are high
● Possible influenza infection |
Negative results:
Negative predictive values are high
● Possible true negative ● In cases where the epidemiologic history suggests an influenza pandemic outbreak, consider confirming with a more sensitive test |
Positive results:
Positive predictive values are low
● Possible false positive ● Confirmation with a more sensitive test is warranted |
| Rapid NAAT, RT-PCR | Negative results:
Negative predictive
values are low
● Possible true negative result if the patient does not present with lower respiratory tract infection ● Consider the possibility of a false negative if the result is from an upper respiratory specimen from an inpatient ● Consider obtaining a lower respiratory specimen if the upper respiratory specimen is negative in an inpatient requiring mechanical ventilation |
Positive results:
Positive predictive values
are high
● Possible influenza infection |
Negative results:
Negative predictive
values are high
● High probability of a true negative result |
Positive result:
Positive predictive values
are low
● Possible false positive |