Aspergillus fumigatus rAsp f1 IgE (RAST), Serum — Qualitative
A blood test that detects IgE antibodies to the rAsp f1 allergen of Aspergillus fumigatus, a mold associated with allergic disease.
["A positive result indicates allergic sensitization to Aspergillus fumigatus but must be interpreted with symptoms and other tests."]
Key facts at a glance
- LOINC
- 51568-4
- Short code
- Deprecated A fumigatus (rAsp f) 1 IgE RAST Ql
- Synonyms
- Deprecated A fumigatus (rAsp f) 1 IgE 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 serum test looks for IgE antibodies directed against rAsp f1, a specific allergen component of Aspergillus fumigatus. It is sometimes described as a RAST or radioallergosorbent test and is reported qualitatively.
Why might I need this test?
Your clinician may order this test when wheezing, coughing, recurrent respiratory infections, or worsening asthma suggests an allergic response to Aspergillus mold. It may also be used when evaluating suspected allergic bronchopulmonary aspergillosis, a condition in which the immune system reacts to Aspergillus in the airways.
How is the test performed?
A blood sample is drawn and the serum is tested for antibodies against the Aspergillus fumigatus rAsp f1 allergen. The laboratory provides a qualitative result, such as positive or negative, based on the test method.
How do I prepare for the test?
No special preparation is usually needed. Tell your clinician if you are taking biologic immune-system treatments, because these may affect antibody test results, and do not stop prescribed medicines unless instructed.
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 shows that IgE antibodies to Aspergillus fumigatus rAsp f1 are present, indicating allergic sensitization. In a person with compatible respiratory symptoms, this may support allergic asthma or allergic bronchopulmonary aspergillosis. The result does not by itself confirm a diagnosis or show the severity of the condition, and a negative result does not completely rule out Aspergillus-related allergy.
Short name
Aspergillus fumigatus-specific IgE
Frequently asked questions
What does a positive result mean?
Does a positive result mean I have an Aspergillus infection?
Can this test be used to monitor treatment?
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