Aspergillus fumigatus rAsp f4 IgE, Qualitative (RAST)
A blood test that detects IgE antibodies to the rAsp f4 component of Aspergillus fumigatus, helping evaluate allergic sensitization.
["A positive result suggests an allergic immune response to Aspergillus fumigatus but must be interpreted alongside symptoms and other tests."]
Key facts at a glance
- LOINC
- 51571-8
- Short code
- Deprecated A fumigatus (rAsp f) 4 IgE RAST Ql
- Synonyms
- Deprecated A fumigatus (rAsp f) 4 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 qualitative blood test measures IgE antibodies directed against rAsp f4, a recombinant component of the mold Aspergillus fumigatus. It is commonly known by the laboratory method RAST.
Why might I need this test?
Your clinician may order this test when asthma, wheezing, recurrent sinus or lung symptoms, or other allergic complaints could be related to Aspergillus exposure. It may also be used when evaluating suspected allergic bronchopulmonary aspergillosis or another fungal allergy.
How is the test performed?
A blood sample is collected and the serum is tested for IgE antibodies to the Aspergillus fumigatus rAsp f4 component. The result is reported as detectable or not detectable rather than as a general concentration.
How do I prepare for the test?
Fasting is usually not required for this test. Follow your clinician's instructions and tell the laboratory if you have recently started or stopped allergy medicines or treatments.
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 detectable result indicates IgE sensitization to the rAsp f4 component of Aspergillus fumigatus. This may support an Aspergillus-related allergy or conditions such as allergic bronchopulmonary aspergillosis when combined with compatible symptoms and findings from other tests. A positive result alone does not establish a diagnosis, and a negative result does not completely exclude Aspergillus allergy.
Short name
Aspergillus fumigatus rAsp f4 IgE
Frequently asked questions
What does a positive result mean?
Does this test diagnose allergic bronchopulmonary aspergillosis?
Can I stop allergy medicine before this 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