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

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

There is no special preparation.

There is no discomfort.

Your health care provider may order this test if you have symptoms or signs of a lung infection, such as if you have a weakened immune system due to certain medicines or diseases such as cancer or HIV/AIDS.

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

Some labs use different measurements or test different samples. Talk to your provider about the meaning of your specific test results.

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

• Aspergillosis
• Blastomycosis
• Coccidioidomycosis
• Cryptococcosis
• Histoplasmosis

There are no risks associated with a sputum fungal smear.

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

Banaei N, Deresinski SC, Pinsky BA. Microbiologic diagnosis of lung infection. In: Broaddus VC, Ernst JD, King TE, et al, eds. Murray and Nadel's Textbook of Respiratory Medicine. 7th ed. Philadelphia, PA: Elsevier; 2022:chap 19.

Saullo JL, Alexander BD. Fungal infections: opportunistic. In: Broaddus VC, King TE, Ernst JD, et al, eds. Murray and Nadel's Textbook of Respiratory Medicine. 7th ed. Philadelphia, PA: Elsevier; 2022:chap 57.

Updated by: Jatin M. Vyas, MD, PhD, Associate Professor in Medicine, Harvard Medical School; Associate in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.