Spirometry is a common breathing test that measures how much air you can inhale and exhale, and the speed at which you can force air out of your lungs. While the actual breathing maneuvers only take a few moments, the entire appointment involves several distinct phases that extend the total duration. The time required for a spirometry test, from check-in to the final discussion, typically ranges from 30 to 60 minutes for the full clinical process. This overall time depends significantly on whether a second round of testing is needed to check for reversibility.
Preparing for the Test
Patient preparation is necessary to ensure the accuracy of the results, beginning before you sit down at the machine. You will typically spend about 5 to 10 minutes upon arrival completing necessary paperwork and having your height and weight recorded. These physical measurements are used by the spirometer software to calculate the predicted normal values for your lung function.
Specific lifestyle adjustments are required in the hours leading up to the test to prevent inaccurate readings. You should avoid eating a large meal within two hours and refrain from heavy exercise for at least 30 minutes beforehand. Additionally, you must not smoke on the day of the test or consume alcohol for at least four hours prior to the appointment.
The most time-sensitive preparation involves certain medications, which may need to be withheld as instructed by your healthcare provider. Short-acting bronchodilators, such as albuterol, are generally avoided for four to six hours before the test. Long-acting bronchodilators may need to be stopped for 24 hours or longer, as their presence could mask an underlying breathing issue.
The Active Testing Time
The physical procedure of breathing into the spirometer is broken down into distinct stages, starting with the initial setup and instruction. Approximately five minutes are spent adjusting the machine, fitting a disposable mouthpiece, and having a soft clip placed on your nose. The technician will then thoroughly explain the forced exhalation maneuver, which is crucial for obtaining reproducible data.
The first phase is baseline testing, where you perform forced breathing maneuvers without medication. To meet American Thoracic Society (ATS) quality standards, you must perform multiple forced exhalations until at least three acceptable and reproducible efforts are recorded. Each maneuver involves taking a deep breath and blowing out as hard and fast as possible for a minimum of six seconds.
The need for multiple attempts means this phase can take between 10 and 15 minutes, as you may require rest periods between efforts. A maximum of eight maneuvers is usually attempted to prevent fatigue and ensure the highest quality results. If the initial results indicate an obstruction, a reversibility test may be required to see if the airways open up with medication.
If required, the second phase involves administering a bronchodilator, such as albuterol, followed by a mandatory waiting period. The drug is administered via an inhaler or nebulizer. You must wait approximately 10 to 15 minutes for the medication to reach its maximum effect, which is necessary to accurately assess the degree of airway improvement.
Following the waiting period, you repeat the spirometry maneuvers in the post-bronchodilator phase. This second set of measurements takes another 5 to 10 minutes of active testing time. The technician will compare the post-medication values for forced expiratory volume in one second and forced vital capacity to the baseline results to determine if the obstruction is reversible.
Post-Test Analysis and Results Discussion
Once the breathing maneuvers are complete, the technician immediately reviews the collected data for quality control. They check the flow-volume loop graphs to ensure the efforts were maximal and sustained, confirming the test meets acceptability and reproducibility criteria. This technical review ensures the data is reliable before being passed to a physician for final interpretation.
The technician will often provide immediate, preliminary feedback on the main measurements, such as the percentages for Forced Expiratory Volume in one second (FEV1) and Forced Vital Capacity (FVC). A brief discussion of these values and what they might suggest can take a few minutes. However, the comprehensive interpretation, which involves grading the severity of any lung impairment, must be performed by a physician.
The final portion of the appointment involves discussing the next steps, which may include scheduling a follow-up appointment or the initiation of new medication. This discussion and wrapping up of the appointment paperwork usually takes between 5 and 10 minutes. While the full, formal report may be sent to your referring physician later, the immediate discussion concludes the time spent in the testing facility.