[Correlation between exhaled nitric oxide and carbon monoxide and allergic rhinitis].

In this study, the level of nasal nitric oxide（nNO）, exhaled nitric oxide（eNO）, and exhaled carbon monoxide（eCO） in patients with allergic rhinitis（AR） were tested, to explore the correlation between nNO, eNO, eCO and AR. A total of 60 AR patientswere enrolled as the allergy group and then divided into mild, medium and severe subgroups according to symptom scores. 30 healthy volunteers were recruited as control group. The levels of nNO, eNO and eCO were detected in AR group, AR subgroups and control group. The levels of nNO, eNO and eCO in AR group were higher than those in control group（<0.05）. nNO, eNO and eCO levels were positively correlated with symptom scores（<0.05）.Pairwise comparison was used between mild, moderate and severe subgroups. The difference of both nNO and eNO levels between mild, moderate and severe AR subgroups was statistically significant, severe>and moderate>were mild（<0.05）, but there was no significant difference in eNO levels between the mild AR subgroup and the control group（>0.05）. Level of eCO in severe AR subgroup was higher than those in moderate and mild AR subgroups（<0.05）, but there was no significant difference between mild, moderate AR subgroups and control group（>0.05）. nNO, eNO and eCO levels were used as indicators to evaluate the severity of AR, and the receiver operating characteristic（ROC） curves were plotted. The area under curve（AUC） was 0.978, 0.786 and 0.577, respectively. Taking eCO level as the indicator for disease assessment of severe AR, the AUC was 0.728. It showed that nNO had a high accuracy in evaluating the severity of AR, eNO had a certain accuracy in evaluating the severity of AR, and eCO had a certain accuracy in the assessment of severe AR. The detection of nNO, eNO and eCO levels can be used as an objective assessment method of the severity of AR.