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Spirometry is a simple non-invasive test to measure the function of the lungs. It is used mainly for detection and quantitation of airflow obstruction and assists in the diagnosis of dyspnea (breathlessness), as well as determines the severity of Chronic Obstructive Pulmonary Disease (COPD).

Measuring the rate at which the lung changes volume during forced breathing maneuvers, spirometry begins with a full inhalation, followed by a forced expiration that rapidly empties the lungs. Expiration is continued for as long as possible or until a plateau in exhaled volume is reached.

Spirometry is available at all diagnostic centres located at National Healthcare Group and National University Polyclinics. 

Who should come for Spirometry?  

  1. Smokers above 40 years of age.
  2. Ex-smokers.
  3. Asthmatics.
  4. Patients with chronic coughs or episodes of wheezing or dyspnea
  5. Patients whose occupations may expose them to respiratory irritants such as fumes and dusts.

Preparation for a pulmonary function test.   

  1. 24 hours before test:
    • Stop taking some or all of your medication as advised by your doctor/nurse.
    • Have a good night sleep before the test as tiredness may affect the accuracy of the test.
  2. 8 hours before test:
    • Do not smoke or eat a heavy meal.
  3. 4 hours before the test:
    • Do not carry out any strenuous activity.
    • Wear comfortable clothes when you come for the test.
    • Wear loose, non-restrictive clothes that do not restrict the movement of the chest when you come for the test.

Medications to avoid before test.

For accuracy of the test results, you are advised not to take any of the following medications (if possible) according to the hours indicated below.

Bronchodilators/Inhalers to be avoided:

6 hours before test 12 hours before test 24 hours before test Bronchodilators to be avoided
  • Atrovent
  • Atrovent
  • Berodual
  • Bricanyl
  • Berotec
  • Buventol
  • Duovent
  • Ipratran
  • Ipratropium
  • Salbuair
  • Saldolin
  • Sabutamol
  • Ventolin
  • Volmax  
  •  Atimos
  • Foradil
  • Foster
  • Oxis
  • Seretide
  • Serevent
  • Symbicort 
  • Spiriva

Tablets to be avoided:

6 hours before test 12 hours before test 24 hours before test Tablets to be avoided
  • Anasma
  • Apo-salvent
  • Asmol
  • Asmalin
  • Brethmol
  • Butylin
  • Dhatalin
  • Medolin
  • Sp-broncovent
  • Zenmolin
  • Bambec
  • Apo-theo LA
  • Nuelin
  • Theolin
  • Theophylline
  1. Your height and weight will be taken.
  2. The test will be performed with you seated upright.
  3. You need to take a deep breathe and exhale hard & fast into the spirometer until you are unable to exhale anymore.
  4. You are not to lean forward during the procedure.
  5. You may be required to repeat the same test a few times to ensure consistent results.
  6. A bronchodilator challenge test (Post test) will be performed upon your doctor's request.
  7. Before performing the post test, you will need to take 1-2 puffs of a short-acting inhaler and rest for at least 15 minutes before repeating Step 3.
  8. The entire spirometry test takes approximately 20 to 45 minutes.
  9. The test results will be assessed and reviewed by your attending doctor for follow-up management.
Spirometry Procedure 1
Spirometry Procedure 2
Spirometry Procedure 3


Prior appointment is required for spirometry.

Please be punctual on the day of your appointment. If you feel unwell on the day of the test or are unable to make it for the appointment, please contact 6275-6443 to reschedule.

Interpretation of Results

The test results will be assessed and reviewed by your attending doctor for follow-up management.


Payment can be made via Cash or NETS.

Other Information

For FAQs on Spirometry, click here.

Last Updated 29 March 2018
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