Table 3

Diagnostic accuracy of FeNO testing (≥35 ppb) in diagnosing asthma compared with traditional methods3 4

TestPopulationSensitivity (95% CI)Specificity (95% CI)NPV (95% CI)PPV
(95% CI)
Quality of evidence
FeNOChildren57%87%49%90%High—no risk of bias, inconsistency or indirectness
Adults43% to 88%60% to 92%65% to 93%54% to 95%Moderate—no risk of bias, serious indirectness
SpirometryChildren52%73%49%75%
Adults23% to 47%31% to 100%18% to 73%45% to 100%Moderate—no risk of bias, serious indirectness
Peak flowChildren50%72%74%48%High—no risk of bias, inconsistency or indirectness
Adults46%80%10%97%
Bronchodilator reversibilityChildren50%86%
Adults17% to 69%55% to 81%22% to 68%53% to 82%Very low—serious risk of bias, inconsistency and indirectness
  • FeNO, fractional exhaled nitric oxide; NPV, negative predictive value; PPV, positive predictive value.