Sputum smear (KOH test) is a test for the presence of fungal microorganisms in sputum.

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 potassium hydroxide (KOH) and examined under the microscope. If it is positive, fungal cells can be observed.

There is no special preparation.

There is no discomfort.

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

No presence of organisms is normal.

Abnormal results indicate the presence of fungus such as histoplasmosis, coccidioidomycosis, or blastomycoses. White blood cells called eosinophils may also be present.

Additional conditions under which the test may be performed:

• Acute pulmonary eosinophilia (Loeffler's syndrome)
• Coccidioidomycosis; acute (primary) pulmonary
• Coccidioidomycosis; disseminated

There are no risks.

Not applicable.