Bovine Serum Albumin-Specific IgE Antibody (RAST), Qualitative
A blood test that detects IgE antibodies to bovine serum albumin (BSA), a cow-milk protein, to assess possible IgE-mediated milk allergy.
["Detected BSA-specific IgE may support an allergy to bovine serum albumin, but results must be compared with your symptoms."]
Key facts at a glance
- LOINC
- 19046-2
- Short code
- Deprecated BSA IgE RAST Ql
- Synonyms
- Deprecated BSA 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 looks for IgE antibodies directed against bovine serum albumin, a protein found in cow's milk. It is a type of allergen-specific IgE, sometimes described as a RAST-style assay.
Why might I need this test?
A clinician may order it when cow's-milk allergy is suspected, particularly in a person with hives, swelling, wheezing, vomiting, or other symptoms after exposure to milk products. It may also be used to evaluate an allergic reaction to bovine proteins.
How is the test performed?
A blood sample is collected, and the laboratory tests the sample for IgE reactivity to bovine serum albumin. A qualitative result generally reports whether antibodies to BSA were detected rather than providing a numerical concentration.
How do I prepare for the test?
No special preparation is usually required. Antihistamines and some other allergy medicines can affect results, so tell your clinician about all medications and supplements; do not stop prescribed medicine 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.
Detected BSA-specific IgE indicates immune sensitization to bovine serum albumin and may support cow's-milk allergy when it matches the clinical history. A positive result does not by itself prove that symptoms are caused by BSA, and skin symptoms can occur without detectable specific IgE. Interpretation should therefore be done by a clinician using symptoms, exposure history, and other allergy tests.
Short name
Bovine Serum Albumin IgE Test
Frequently asked questions
What does a positive result mean?
Does a negative result rule out cow's-milk allergy?
Should I stop allergy medicines before the 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