Trichophyton vulgaris IgG Radioallergosorbent Test (RAST), Qualitative
A qualitative blood test that detects IgG antibodies directed against the fungus Trichophyton vulgaris, a cause of ringworm and other fungal skin infections.
["A positive result shows an immune response to Trichophyton vulgaris but does not by itself prove that a fungal infection is causing your symptoms."]
Key facts at a glance
- LOINC
- 25539-8
- Short code
- Deprecated T vulgaris IgG RAST Ql
- Synonyms
- Deprecated T vulgaris IgG RAST Ql
- Category
- liver
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 10
- Ref high
- 40
- Critical range
- — – 500 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 84484
- SNOMED
- 302774002
- 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?
This test examines a blood sample for IgG antibodies to Trichophyton vulgaris, a dermatophyte fungus that can cause ringworm and other skin, hair, or nail infections. It is reported as positive, negative, or sometimes equivocal. RAST is an older term often used for allergy antibody testing, so the exact antibody class and method should be confirmed on your laboratory report.
Why might I need this test?
This test may be used in selected cases to help evaluate a suspected fungal infection or exposure to Trichophyton vulgaris. It can also appear on older allergy-related reports, although IgG antibodies generally reflect exposure rather than the immediate allergic response measured by IgE-specific testing.
How is the test performed?
A laboratory professional draws blood from a vein and analyzes it using an immunoassay or RAST-type method. The result is qualitative, meaning it reports whether detectable antibodies were found rather than providing a specific antibody concentration.
How do I prepare for the test?
No special preparation is usually required for this blood test. Tell your clinician if you have a bleeding disorder, are taking anticoagulant medicines, or have recently received biologic therapy or immune-suppressing treatment, because these factors may affect interpretation.
Reference range
Adult: 10-40 U/LN/A
No special preparation required. Avoid fatty meals before the test if possible.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
A positive result indicates that IgG antibodies to Trichophyton vulgaris are detectable and may reflect current or previous exposure. It does not by itself identify the location or severity of an infection or prove that the fungus is causing symptoms. If the concern is an immediate allergy, IgE-specific testing and clinical evaluation may be more appropriate than IgG testing.
Short name
Trichophyton vulgaris IgG antibodies, qualitative
Frequently asked questions
Does a positive result mean I have ringworm?
Can this test tell me which part of my body is infected?
Is RAST the same as an IgE allergy 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 17, 2026. · Read our editorial policy