Candida Antigen in Serum (Quantitative)
This test detects the presence of Candida antigens in your blood, which may indicate an active fungal infection caused by yeast like *Candida*. It helps doctors assess if you have a systemic fungal infection beyond what’s visible on skin or mucous membranes.
["This test can help identify serious fungal infections that may require urgent medical attention."]
Key facts at a glance
- LOINC
- 27391-2
- Short code
- CANDM
- Synonyms
- Candida IgM Ser IA-aCnc
- Category
- chemistry
- Sample
- serum
- Container
- Serum separator tube (SST) or red-top vacuum tube without anticoagulant; serum aliquot transferred to a sterile, leak-proof transport tube
- Units
- N/A
- Ref low
- 9
- Ref high
- 11
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- Immunoassay (e.g., Enzyme Immunoassay/EIA or Chemiluminescent Immunoassay/CLIA) for detection of IgM antibodies to Candida species
- CPT
- 86645
- SNOMED
- 1217210007
- Specimen volume
- 1.0 mL serum (minimum 0.5 mL)
- Stability
- Stable for 24 hours at room temperature (15-25°C); 7 days at 2-8°C; up to 30 days frozen at -20°C or colder. Avoid repeated freeze-thaw cycles.
- Hemolysis max
- 100
- Lipemia max
- 100
- Icterus max
- 50
- TAT
- 24–72 hours
- Order
- routine
What Does This Test Measure?
The test measures specific antigens produced by *Candida* species in your serum. These antigens are fragments of the fungus that your immune system can detect. The presence of these antigens suggests an active infection, even if the fungus isn’t visible through other tests like blood cultures or imaging.
Why Might Your Doctor Order This Test?
Your doctor may recommend this test if you have symptoms of a fungal infection—such as fever, fatigue, or unexplained infections—and have risk factors like weakened immunity (e.g., from HIV, chemotherapy, or long-term steroid use), recent surgery, or a history of candidiasis. It’s also used in patients with persistent bloodstream infections that don’t clear with antibiotics.
How Is the Test Performed?
A blood sample is drawn from a vein in your arm. The serum portion is separated and tested for Candida antigens using a sensitive immunoassay method. The result is reported as either positive or negative, or sometimes as a quantitative value indicating antigen levels.
What Are Possible Results?
A positive result means Candida antigens were detected in your blood, suggesting an active fungal infection. A negative result means no detectable antigens were found, but this doesn’t always rule out infection—other tests may be needed. False negatives can occur if the infection is mild or localized.
Reference range
Negative: <9.0 AU/mL (arbitrary units); Equivocal: 9.0-11.0 AU/mL; Positive: >11.0 AU/mL (reference ranges vary by assay manufacturer; values should be interpreted using the laboratory's established reference interval)N/A
No special patient preparation is required. Fasting is not necessary. Samples may be collected at any time of day.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Candida Antigen Test
Frequently asked questions
If you have a positive result, it signals a need for further evaluation, including blood cultures or imaging, to confirm the type of Candida infection and guide treatment. Early detection is critical for managing serious infections, especially in immunocompromised patients, where complications can be life-threatening.
This test is primarily for detecting systemic (whole-body) Candida infections, not localized infections like oral thrush or vaginal yeast infections. Those are typically managed with topical treatments.
A negative result doesn’t always mean you’re infection-free. Other causes of symptoms (like infections, inflammation, or other medical conditions) could explain your concerns. Talk to your doctor about additional tests or follow-up.
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 15, 2026. · Read our editorial policy