Sputum fungal smear
A sputum fungal smear is a laboratory test that looks for fungus in a sputum sample. Sputum is the material that comes up from air passages when you cough very deeply.
KOH test; Fungal smear - sputum; Fungal wet prep; Wet prep - fungal
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. A small amount is lightly smeared onto a microscope slide and mixed with potassium hydroxide (KOH). The slide is examined under the microscope and checked for fungus parts.
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 abnormal sputum production or signs of a lung infection.
A normal test should show no fungus on the microscope slide.
Note: Normal value ranges may vary slightly among different laboratories. 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:
What the risks are
There are no risks associated with a sputum fungal smear.
Limper AH. Overview of pneumonia. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 97.
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.