How the Test is Performed

A sputum sample is needed. You will be asked to cough deeply and spit any material that comes up from your lung into a special container.

The sample is sent to a lab and examined under a microscope.

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

Your doctor may order this test if you have symptoms or signs of a lung infection, especially if you have a weakened immune system due to certain medicines or diseases such as cancer, HIV, or AIDs.

Normal Results

A normal (negative) result means no fungus was seen in the test sample.

Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your doctor about the meaning of your specific test results.

What Abnormal Results Mean

Abnormal results may be a sign of a fungal infection. Such infections include:

• Aspergillosis
• Blastomycosis
• Coccidioidomycosis
• Cryptococcus
• Histoplasmosis

An abnormal result may also be due to acute pulmonary eosinophilia (Loeffler syndrome).

Risks

There are no risks associated with a sputum fungal smear.

Alternative Names

KOH test; Fungal smear - sputum; Fungal wet prep; Wet prep - fungal

References

Limper AH. Overview of pneumonia. In: Goldman L, Ausiello D, eds.Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 97.

Updated: 4/6/2012

Reviewed by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School, Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.