Measurement of levels of fractional exhaled nitric oxide in patients with pulmonary tuberculosis

SETTING: The role of fractional exhaled nitric oxide (FeNO) in the diagnosis and treatment of pulmonary tuberculosis (PTB) is uncertain.

OBJECTIVE: To examine the value of FeNO as a biomarker for PTB.

DESIGN: Baseline FeNO levels were compared in 69 PTB patients and 118 healthy controls. The correlation between baseline FeNO levels and clinical variables of tuberculosis were studied. FeNO levels were checked twice in the PTB group, at diagnosis and after 2 months of anti-tuberculosis medication, and factors affecting changes in FeNO levels after treatment were analysed.

RESULTS: FeNO levels were not significantly different in the PTB group and controls (mean ± standard deviation 27.7 ± 17.6 parts per billion [ppb] vs. 27.0 ± 10.8 ppb, P = 0.531). In a multivariate regression analysis, no variable was shown to affect FeNO levels at diagnosis. FeNO levels did not significantly change after 2 months of treatment (26.8 ± 18.3 ppb vs. 24.0 ± 10.7 ppb, P = 0.257). Only PTB with a high FeNO level (>25 ppb) was related to a decline in FeNO levels after 2 months of treatment.

CONCLUSION: FeNO levels do not appear to be affected in PTB patients.