['Absenteeism from outpatient appointments is common. Telephone appointment-reminder calls reduce outpatient-appointment absenteeism in many clinic settings.', 'To determine if telephone appointment-reminder calls reduce outpatient absenteeism at a hospital-based pulmonary function laboratory.', 'We conducted a retrospective review of our pulmonary function laboratory\'s outpatient appointment records from April to November 2004. Data were collected from consecutive outpatient appointments, including patient age, sex, whether a telephone appointment-reminder call was successfully made, and whether the patient showed up for the scheduled test. We performed 3 analyses. Differences in absenteeism between the groups was the primary outcome measure. First, appointments were separated into 2 groups: (1) appointments for which a reminder call was attempted ("called" group) and (2) appointments for which a reminder call was not attempted ("not-called" group). The appointments were then separated into 2 further groups: (1) the reminder call was successfully achieved ("contacted" group) and (2) the patient either was not called or was called but could not be reached ("not-contacted" group). Finally, the contacted group was separated into 2 further groups: (1) reminder calls that resulted in direct conversation with an appropriate person at the patient\'s listed telephone number, and (2) reminder message left on an answering machine.', 'Data were collected from 515 consecutive outpatient appointments; 45 (8.7%) of these patients did not show up for testing. The absentee rate was 4.7% (n = 10) in the called group and 11.6% (n = 35) in the not-called group (p = 0.0066). In the called group, 6.5% (n = 14) could not be reached. The absentee rate was 4% (n = 8) in the contacted group and 11.7% (n = 37) in the not-contacted group (p = 0.0021). We found no difference in absenteeism between patients who received reminders via direct conversation (4.2%) and those who had a reminder message left on an answering machine (3.7%) (p > 0.05).'] Does the effect of telephone appointment-reminder call on outpatient absenteeism in a pulmonary function laboratory?