PFT (Pulmonary Function Test)

PFT (Pulmonary Function Test)

PFTs, Pulmonary Function Tests, are diagnostic tests used to evaluate the respiratory system of the patient. This evaluation includes the measurement of lung capacity, volume, and gas exchange.

There are 2 methods for PFT

  • Spirometry: With a spirometer, the respiratory patterns of the patient are identified, and chronic diseases such as asthma, COPD, and pulmonary fibrosis can be diagnosed.
  • Plethysmography: An instrument where the patient sits or stands inside an air-tight box and measures changes in volume within an organ or whole body.

These methods can be used together or separately.

With PFT, tidal volume, vital capacity, total lung capacity, FVC, FEV1, and many other parameters for lung function can be measured. Normal values can vary from patient to patient with respect to age, gender, ethnicity, and health history. PFTs can be done in regular check-ups, allergy diagnostics, or respiratory care purposes.


  1. Pulmonary Function Tests.” Johns Hopkins Medicine

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