Sputum smear (KOH test)

Alternative names:

KOH test

How the test is performed:

Obtain a sputum sample by coughing deeply and expelling the material that comes from the lungs (sputum) into a specimen container. A smear of sputum is prepared with a potassium hydroxide (KOH) and examined under the microscope. If it is positive, fungal cells can be observed.

How to prepare for the test:

There is no special preparation.

How the test will feel:

There is no discomfort.

Why the test is performed:

The test may be performed when there is abnormal sputum production or when an infection of the lungs is suspected.