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Fungal Antigen (1,3-β-D-Glucan) in Serum

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

This blood test measures levels of a specific sugar molecule found in the cell walls of certain fungi, helping detect infections caused by invasive fungal diseases.

Quick summary

["This test helps identify fungal infections that may not be visible on other tests alone."]

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

Key facts at a glance

LOINC
77203-8
Short code
Smut fungi IgE Qn
Synonyms
Smut fungi IgE Qn
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 Measuring?

The test looks for 1,3-β-D-glucan, a carbohydrate unique to the cell walls of many fungi. It can help detect infections like candidiasis (yeast), aspergillosis (mold), or cryptococcosis (another type of mold).

Why Might Your Doctor Order This Test?

Your doctor may recommend this test if you have symptoms like fever, fatigue, or organ dysfunction—especially if you’re at higher risk for fungal infections, such as from weakened immunity (e.g., due to chemotherapy, HIV, or organ transplants).

What Does a Positive Result Mean?

A positive result suggests the presence of fungal material in your blood or tissues, which may indicate an invasive fungal infection. However, it’s not definitive—your doctor will consider other factors, like symptoms and culture results, before diagnosing.

What Are Common Causes of Abnormal Results?

False positives can occur with certain bacteria or other substances, and false negatives may happen if the infection isn’t widespread. Results can also vary based on timing (e.g., taken too early after infection onset).

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

1,3-β-D-Glucan Test

Frequently asked questions

Why was I asked to take this blood sample?
Your doctor may have ordered this test because you have symptoms that could be caused by a fungal infection, such as unexplained fevers, weight loss, or organ problems. It’s also used if you’re undergoing treatment that weakens your immune system, increasing your risk of fungal infections.
What does a high or low level of 1,3-β-D-glucan mean?
A high level suggests possible fungal infection, but it doesn’t confirm the diagnosis alone. Your doctor will review the result with your symptoms, medical history, and other tests to determine the next steps. A low level means the test did not detect significant fungal material in your blood.
Can I eat or drink anything before this test?
You can usually eat and drink normally before this test unless instructed otherwise. However, avoid alcohol for 24 hours before your blood draw, as it may affect test results.
  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