: Galactomannan Antigen, Serum or Plasma
: This test detects galactomannan, a carbohydrate component of certain mold cell walls, in a sample of serum or plasma. It is used to help identify invasive Aspergillus infection, especially in people with weakened immune systems.
[": A galactomannan antigen test looks for evidence of Aspergillus mold in the blood and is often used alongside imaging, cultures, and clinical findings."]
Key facts at a glance
- LOINC
- 108700-6
- Short code
- Galactomannan Ag Msmt SerPl
- Synonyms
- Galactomannan Ag Msmt SerPl
- 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 This Test Measures
: Galactomannan is a polysaccharide released from the cell walls of Aspergillus species and some related molds as they grow. Detecting it in blood can provide a clue that such a mold is present in the body, even when cultures do not grow the organism.
: Why Your Clinician May Order It
: The test is most often ordered for people at high risk of invasive aspergillosis, such as those receiving chemotherapy, transplant recipients, or others with prolonged low white blood cell counts. It may also be used to monitor response during treatment for a known Aspergillus infection.
: How the Sample Is Collected
: A blood sample is drawn from a vein, usually in the arm, and the serum or plasma is separated for testing. No special preparation is typically required, though your care team will give any specific instructions.
: What Results Can Mean
: A positive or elevated result suggests that galactomannan from Aspergillus or a related mold may be present and is usually interpreted together with symptoms, imaging, cultures, and other tests. A negative result makes invasive Aspergillus infection less likely but does not rule it out, and results can be affected by certain antibiotics, antifungals, and other factors. Your clinician will interpret the result in the context of your overall health.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
: Galactomannan antigen testing is a supportive tool for detecting invasive aspergillosis and is not a stand-alone diagnosis. Its performance depends on the patient population, specimen type, timing of collection, prior antifungal therapy, and possible cross-reactions. Results should always be integrated with clinical evaluation, imaging, culture, and, when appropriate, repeat testing.
Short name
: Galactomannan Ag
Frequently asked questions
: Does a positive galactomannan result always mean I have an Aspergillus infection?
: Can this test be negative even if an infection is present?
: Do I need to fast or prepare for this blood test?
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