What should you know about glottic closure spirometry?

Glottic closure during spirometry can interrupt airflow, so the result may need careful interpretation or repeat testing. The glottis is the opening between the vocal cords. It can narrow briefly when you forcefully breathe out, producing an unusual tracing or a sensation of throat tightness.

Spirometry measures how much air you move and how quickly you blow into a [Spirometer](/technology/spirometer/). A good effort requires a fast, sustained exhalation. If the vocal cords close instead of staying open, the measured flow can fall suddenly and the test may not represent your usual lung function. Coughing, poor seal, anxiety or technique can create similar difficulties. This finding is not the same as a confirmed diagnosis of asthma or another lung condition.

Tell the tester immediately if your throat feels tight, your voice changes, or you cannot continue. Follow the preparation instructions about medicines, smoking and meals; do not stop prescribed treatment unless the testing team tells you to. The clinician may coach your posture and breathing, allow recovery time, or arrange formal [Spirometry](/treatments/diagnostics-and-screening/spirometry/) review. Keeping a record of wheeze, cough and triggers can help place the tracing in context.

Get urgent help for severe breathlessness, blue or grey lips, fainting, chest pain, or throat swelling that does not quickly ease. Contact your clinician when breathing episodes recur, exercise becomes difficult, or cough persists. Assessment may consider [Asthma](/conditions/asthma/), [COPD](/conditions/copd/), [Bronchiectasis](/conditions/bronchiectasis/) or [Chronic Cough](/conditions/chronic-cough/), alongside upper-airway causes.

Ask whether the tracing was technically adequate, whether another breathing test is useful, and how your inhalers should be used before testing. If you smoke, ask about a [Smoking Cessation Programme](/treatments/lifestyle-and-wellness/smoking-cessation-programme/); ask whether [Inhaler Therapy](/treatments/medical-management/inhaler-therapy/) fits your symptoms.