Validation of a life quality (LQ) test for asthma

The American College of Allergy, Asthma, and Immunology (ACAAI) developed a questionnaire, the Life Quality (LQ) Test, for use in its Nationwide Asthma Screening Program. The test is intended as a tool to help individuals with breathing problems determine if they have asthma or, for those already diagnosed with asthma, if their asthma is under control. We attempted to assess whether the LQ Test was a valid tool for use in the screening program.

The objective of this study was to validate the LQ Test by determining whether a high score on the LQ Test is a positive predictor of a clinical diagnosis of asthma.

The 20-question LQ Test was prospectively distributed and self-administered to new patients on their first visit to an asthma and allergy clinic. Total LQ scores were recorded for each patient as the sum of all positive 'yes' responses to the test. All patients were subsequently diagnosed by an allergist as having asthma or not having asthma. The LQ Test also was administered to a group of individual patients who were seen in a dental office. This group of patients, who had no known breathing problems, served as a control.

The clinic patients who were subsequently diagnosed with asthma had the highest average LQ score (9.31), 3.9 times higher than the average score for clinic patients diagnosed as not having asthma (2.39), and 8 times higher than the average score for the control group (1.15).

Higher LQ scores correlate with a higher probability of a positive diagnosis, initially making the LQ Test questionnaire a valid tool to help predict which individuals are more likely to be diagnosed with asthma.