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Fungal antigen in serum/plasma (quantitative)

Published: August 9, 2026Updated: August 16, 2026

This test measures the presence of fungal antigens in your blood, which can help detect certain fungal infections.

Quick summary

["Detects fungal infections early with a simple blood test."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
55306-5
Short code
Fungus Nail Ql KOH Prep
Synonyms
Fungus Nail Ql KOH Prep
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
koh-preparation
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 This Test Measures

The test looks for specific molecules (antigens) produced by certain fungi in your bloodstream. These antigens can indicate an active fungal infection, even before symptoms appear.

How the Test Works

A small blood sample is drawn and analyzed using an immunoassay method to detect fungal antigens. This helps identify infections caused by organisms like Cryptococcus or other systemic fungi.

When You Might Need This Test

Your healthcare provider may recommend this test if you have symptoms of fungal infection (e.g., fever, fatigue, skin changes) or if you’re at higher risk due to conditions like weakened immunity, cancer treatments, or chronic illnesses.

Common Uses

This test is particularly useful for diagnosing fungal infections in immunocompromised patients, monitoring chronic fungal conditions, or evaluating patients with unexplained symptoms suggestive of infection.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Fungal Antigen Test

Frequently asked questions

This test helps confirm fungal infections that may not be visible on standard blood tests or imaging, allowing for timely treatment with antifungal medications.
Yes, this test can detect fungal infections in your blood even before other signs appear, helping guide treatment decisions.
The test uses a blood sample and an immunoassay method to detect fungal antigens, which are molecules produced by fungi. It’s not a culture test, so it may not identify the specific type of fungus.
Antifungal medications are typically prescribed based on test results, but your doctor may also consider other factors like symptoms, medical history, and culture results.
False positives can rarely occur, especially if you have recent exposure to fungi or certain medications. Your doctor will discuss results and next steps with you.
No, this test does not provide information about the type of fungus causing the infection. If needed, additional tests (like cultures) may be performed to identify the specific organism.
  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 16, 2026. · Read our editorial policy