OBJECTIVE: Periodic assessment of health status is critical for risk stratification and case management. This study tested a simple telephone-based interview to assess current asthma status (past hour) and determined the extent to which a questionnaire-based measure could predict peak expiratory flow (PEF). METHODS: Thirty-nine adult asthma patients (56% participation) were randomly selected from among managed care patients with a medical or pharmacy claim for asthma in the six months prior to interview. Volunteers completed four weekly telephone interviews to assess current asthma status. Using a portable device, two PEF measurements were taken after each interview. The interview screened for seven asthma symptoms. Using 10-point anchored scales, volunteers also rated their abilities to: a) take a full and complete deep breath; b) perform self-defined moderately demanding activities; and c) perform self-defined demanding activities, during the recall period. Linear regression was used to model percent-predicted PEF. Covariates that contributed significantly to improving model fit were retained. Linear and nonlinear terms were tested. We fit the model using baseline data and tested it on follow-up data. RESULTS: A linear model including the average of: a) the three scaled covariates (ability to take a full and complete deep breath, perform moderately-demanding activities, and perform demanding activities); b) body mass index; and c) an interaction term, correlated well with percent-predicted PEF (r=0.72). When applying the model to follow-up data, the correlation coefficient remained high (r=0.63). CONCLUSIONS: This 2-minute telephone-based interview provides a rapid, simple, and accurate alternative to more complicated and time intensive measures to assess asthma status.