What To Expect Before Lung Function Tests

If you take breathing medicines, your doctor may ask you to stop them for a short time before spirometry, a lung volume measurement test, or a lung diffusion capacity test.

No special preparation is needed before pulse oximetry and arterial blood gas tests. If you're being treated with oxygen, your doctor may ask you to stop using it for a short time before the tests. This is done to check your blood oxygen level without the added oxygen.