Skip to content

Galactomannan (Serum/Plasma)

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

This test measures the presence of galactomannan, a fungal polysaccharide that can indicate infection by certain fungi, such as *Aspergillus*. It is often used in high-risk patients, like those with weakened immune systems.

Quick summary

["Helps detect fungal infections in blood or lung samples."]

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

Key facts at a glance

LOINC
35383-9
Short code
Galactomannan Ag SerPl-aCnc
Synonyms
Galactomannan Ag SerPl-aCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
86038
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 Galactomannan Used For?

Galactomannan is primarily used to screen for *Aspergillus* fungal infections, particularly in individuals at higher risk, such as those with cancer, organ transplants, or severe immune deficiencies. It may also be used in patients with persistent lung symptoms or known exposure to fungi.

How Is the Test Performed?

This test involves drawing blood (serum or plasma) and analyzing it for the presence of galactomannan using a sensitive immunoassay method. Results are typically reported as either positive or negative, rather than a specific concentration.

Why Might You Need This Test?

Your healthcare provider may recommend this test if you have symptoms like fever, cough, or breathing difficulties, or if you have a condition that increases your risk of fungal infections (e.g., chemotherapy, HIV, or a recent transplant). It helps guide treatment decisions for fungal infections.

What Does a Positive Result Mean?

A positive result suggests the presence of *Aspergillus* or another galactomannan-producing fungus. This does not confirm the exact type of infection but signals that further testing (like culture or imaging) is often needed to confirm the diagnosis and guide treatment.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Detecting Fungal Infections Early

Short name

Galactomannan Test

Frequently asked questions

Why was this test ordered?
Your doctor may have ordered this test to check for signs of fungal infection, especially if you have a weakened immune system, recent medical procedures, or symptoms like persistent cough or fever. Early detection can improve treatment outcomes.
What does a negative result mean?
A negative result means no detectable galactomannan was found in your sample. However, it does not rule out fungal infection entirely. If you have symptoms or risk factors, further testing or monitoring may still be needed.
How soon will I get my results?
Results are usually available within 24 to 48 hours, depending on lab processing times. Your healthcare provider will discuss the results with you and explain next steps, such as additional tests or treatment plans.
  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