Yeast Identified in Sputum by KOH Preparation
A sputum microscopy test that uses potassium hydroxide to help detect and identify yeast in respiratory secretions.
["Yeast in sputum may reflect normal colonization, contamination, or a respiratory yeast infection, depending on symptoms and other findings."]
Key facts at a glance
- LOINC
- 55316-4
- Short code
- Yeast Spt Ql KOH Prep
- Synonyms
- Yeast Spt Ql KOH Prep
- Category
- liver
- Sample
- sputum
- Container
- Sterile sputum container
- Units
- N/A
- Ref low
- 10
- Ref high
- 40
- Critical range
- — – 5 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- koh-preparation
- CPT
- 84484
- SNOMED
- 302774002
- Specimen volume
- 3-5 mL
- Stability
- Room temperature: 2h, Refrigerated: 24h
- TAT
- 4–24 hours
- Order
- routine
What is this test?
This test examines sputum, or mucus coughed up from the lower respiratory tract. Potassium hydroxide (KOH) preparation helps make yeast cells visible under a microscope so they can be reported as present or absent.
Why might I need this test?
A clinician may order this test when you have a persistent cough, fever, wheezing, shortness of breath, or other symptoms that could be related to a respiratory infection. It may also be used to evaluate suspected fungal disease or immune-related lung conditions.
How is the test performed?
A sputum sample is collected and mixed with KOH. The laboratory examines the prepared sample under a microscope and reports whether yeast was identified. This is a rapid, qualitative test and does not measure the amount of yeast.
How do I prepare for the test?
Follow the laboratory or clinician's instructions for collecting sputum. You may be asked to cough material from deep in the chest into a sterile container, and specific timing or oral-care instructions may apply. No special diet or fasting is generally required.
Reference range
Adult: 10-40 U/LN/A
No special preparation required. Avoid fatty meals before the test if possible.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Yeast identified in sputum can represent normal colonization, contamination during collection, or infection, particularly in people with weakened immune systems or underlying lung disease. A positive result should be interpreted with symptoms, examination findings, and other microbiologic tests because yeast is not always the cause of illness. A negative result does not completely exclude a fungal infection.
Short name
Yeast, Sputum KOH Prep
Frequently asked questions
Does a positive result mean I have a yeast infection?
What does a negative KOH preparation mean?
Is this the same as a yeast culture?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy