Background So far,in China,there has been no effective or easy procedure to define the control of asthma.This studyassesses the validity of Asthma Control Test in Chinese patients.Methods Three questionnaires (Asthma Control Test,Asthma Control Questionnaire and the 30 second asthma test)were administered to 305 asthma patients from 10 teaching hospitals across China.Spirometry was also used.Asthmaspecialists rated the control of asthma according to patients’ symptoms,medications and forced expiratory volume in firstsecond.The patients were divided into noncontrolled group and controlled group according to the specialists’ rating.Reliability,empirical validity and screening accuracy were conducted for Asthma Control Test scores.Screening accuracywas compared among 3 questionnaires.The patients’ self rating and the specialists’ rating were also compared.Results The internal consistency reliability of the 5-item Asthma Control Test was 0.854.The correlation coefficientbetween Asthma Control Test and the specialists’ rating was 0.729,which was higher than other instruments.AsthmaControl Test scores discriminated between groups of patients differing in the percent predicted forced expiratory volumein first second (F=26.06,P<0.0001),the specialists’ rating of asthma control (F=88.24,P<0.0001) and the AsthmaControl Questionnaire scores (F=250.57,P<0.0001).Asthma Control Test showed no significant difference with AsthmaControl Questionnaire in the percent correctly classified,while the percent correctly classified by Asthma Control Testwas much higher than 30 second asthma test.The patients’ self rating was the same as assessment of the specialists(t=0.65,P=0.516).Conclusion The Asthma Control Test is an effective and practicable method for assessing asthma control in China.Chin Med J 2007;120(12):1037-1041 Background So far, in China, there has been no effective or easy procedure to define the control of asthma. This study has assessed the validity of Asthma Control Test in Chinese patients. Methods Three questionnaires (Asthma Control Test, Asthma Control Questionnaire and the 30 second asthma test) were administered 305 asthma patients from 10 teaching hospitals across China. Spirometry was also used. Asthmaspecialists rated the control of asthma according to patients’ symptoms, medications and forced expiratory volume in firstsecond. The patients were divided into noncontrolled group and controlled group according to the specialists’ rating. Reliability, verification accuracy and screening accuracy were conducted for Asthma Control Test scores. Screening accuracy was compared among 3 questionnaires. The patients’ self rating and the specialists’ rating were also compared. Results The internal consistency reliability of the 5-item Asthma Control Test was 0.854.The correlation coefficientbetween Asthma Cont rol Test and the specialists ’rating was 0.729, which was higher than other instruments. State Control Test scores discriminated between groups of patients differing in the percent predicted forced expiratory volume in first second (F = 26.06, P <0.0001), the specialists’ rating of Asthma Control Test showed no significant difference with AsthmaControl Questionnaire in the percent correctly classified, while also demonstrating the beneficial effects of asthma control (F = 88.24, P <0.0001) and the AsthmaControl Questionnaire scores (F = 250.57, P <0.0001) Testwas much higher than 30 second asthma test. The patients’ self rating was the same as assessment of the specialists (t = 0.65, P = 0.516). Conclusions The Asthma Control Test is an effective and practicable method for assessing asthma control in China. Chin Med J 2007; 120 (12): 1037-1041