You should generally avoid using your short-acting inhaler for 4 to 6 hours before the test to ensure the results reflect your baseline lung function. Long-acting bronchodilators typically require a 24-hour hold period. We always recommend checking your specific appointment letter or calling our clinic, as 90 percent of diagnostic accuracy depends on following these pre-test instructions. If you experience acute respiratory distress, use your medication immediately and we’ll reschedule your session.