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Yeast and Pseudohyphae, Bronchial Specimen — Qualitative (KOH Preparation)

Published: August 9, 2026Updated: August 17, 2026

A microscopic examination of a bronchial specimen that looks for yeast and pseudohyphae, which may be seen with Candida or related fungi.

Quick summary

["A positive result shows fungal yeast forms in the respiratory specimen but must be interpreted with symptoms and other tests."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
55319-8
Short code
Yeast pseudohyphae Bronch Ql KOH Prep
Synonyms
Yeast pseudohyphae Bronch Ql KOH Prep
Category
liver
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
10
Ref high
40
Critical range
— – 500 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
koh-preparation
CPT
84484
SNOMED
302774002
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What is this test?

This test examines a bronchial respiratory specimen for yeast and pseudohyphae. A potassium hydroxide (KOH) preparation is used to help make these fungal forms visible under a microscope.

Why might I need this test?

It may be ordered when a lung infection is suspected, particularly in someone with pneumonia symptoms, chronic lung disease, immune suppression, or recent antibiotic use. It can also help evaluate a respiratory specimen for fungal organisms.

How is the test performed?

A respiratory sample, such as sputum or material obtained during bronchoscopy, is mixed with KOH and examined microscopically. The laboratory reports whether yeast or pseudohyphae are seen.

How do I prepare for the test?

No special medication or food restrictions are usually required, but specimen-collection instructions may vary by setting. Follow the instructions for producing or collecting the sample, and tell the healthcare team about any recent antifungal treatment.

Reference range

Adult: 10-40 U/LN/A

Specimen: serum

No special preparation required. Avoid fatty meals before the test if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Bronchial Yeast and Pseudohyphae, KOH Prep

Frequently asked questions

What does a positive result mean?
Yeast or pseudohyphae were seen in the bronchial specimen. This may indicate a fungal infection, but it can also reflect colonization and requires clinical interpretation.
Does this test identify a specific fungus?
The KOH preparation shows fungal forms but generally does not identify the exact species. Culture or other fungal testing may be needed for more specific identification.
Is a negative result rule out a fungal infection?
No. Fungal organisms may be too few to detect or may be unevenly distributed in the specimen, so a negative result does not completely exclude infection.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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 17, 2026. · Read our editorial policy