Spirometry is a common pulmonary function test (PFT) that measures how much and how quickly you can exhale, yielding FEV1, FVC and the FEV1/FVC ratio to detect obstructive or restrictive lung disease. PFTs include spirometry plus lung volumes and diffusion capacity (DLCO). They’re noninvasive, effort‑dependent tests used for diagnosis, monitoring, pre‑operative assessment and evaluating treatment response.

A normal spirometry result typically shows FEV1 and FVC at or above about 80% of the predicted value for age, sex, height, and ethnicity, with an FEV1/FVC ratio above the lower limit of normal (commonly ≥0.70 in adults). Values below these thresholds suggest obstructive or restrictive patterns and warrant further clinical evaluation.

Cost varies by country and test complexity: in the US a basic spirometry/PFT typically runs about $40–$500 (full lab panels higher); in the UK PFTs are free on the NHS but private tests commonly cost £50–£200; in India PFTs usually range roughly ₹300–₹2,000 at private centers. Final price depends on facility, added measurements (DLCO), and insurance coverage.

To prepare for a pulmonary function test, wear loose, comfortable clothing and avoid heavy meals beforehand. Don’t smoke for at least 6 to 8 hours and skip caffeine or vigorous exercise before the test. Follow your clinic’s instructions about withholding inhalers or other respiratory medicines (timing varies). Bring a medication list, ID and inhalers, arrive early, and tell staff about recent chest surgery or unstable health.

Pulmonary function tests (PFTs) are noninvasive and generally not painful. You’ll breathe through a mouthpiece, sometimes wear a nose clip, and follow breathing maneuvers; forceful exhalations can cause shortness of breath, coughing or lightheadedness. People with severe lung disease, recent chest surgery, or certain heart conditions may feel more discomfort. Tests are supervised and stopped if you become distressed.

Doctors order pulmonary function tests (PFTs) to evaluate how well the lungs work: to diagnose and distinguish obstructive (asthma, COPD) versus restrictive (fibrosis) patterns, assess symptoms like shortness of breath or chronic cough, measure disease severity and gas exchange, monitor progression or treatment response, check bronchodilator reversibility, and for pre‑operative or occupational screening.