Milk-Specific IgE Antibody, Qualitative (RAST Test)
A blood test that checks for IgE antibodies directed against milk proteins to help evaluate possible milk allergy.
["A positive result suggests milk allergy sensitization, but it must be interpreted alongside symptoms and other allergy testing."]
Key facts at a glance
- LOINC
- 15837-8
- Short code
- Deprecated Mare Milk IgE RAST Ql
- Synonyms
- Deprecated Mare Milk 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 test looks for milk-specific IgE antibodies in a blood sample. IgE is an immune-system protein that can develop in response to milk proteins. RAST is a traditional name for this type of allergy antibody testing.
Why might I need this test?
Milk-specific IgE testing may be used when a person has symptoms such as hives, swelling, wheezing, vomiting, or digestive discomfort after eating milk. It can also be used to assess sensitization before an oral food challenge or during evaluation of an existing food allergy.
How is the test performed?
A blood sample is collected and tested in a laboratory using an IgE antibody assay. The qualitative result is generally reported as negative or positive, sometimes with a measurement level that the laboratory compares with its own testing method.
How do I prepare for the test?
Fasting is usually not required for this blood test. Tell your clinician about any medicines you take, particularly antihistamines, because these may affect other allergy tests; do not stop prescribed medicines without medical advice.
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 milk-specific IgE antibodies are present, supporting milk allergy sensitization, but it does not by itself prove that milk causes the person's symptoms. A stronger antibody level generally increases the likelihood of clinical milk allergy, although interpretation depends on the testing method and clinical history. A negative result makes immediate milk allergy less likely but does not completely exclude it, particularly in some people with non-IgE-mediated reactions.
Short name
Milk-Specific IgE (RAST)
Frequently asked questions
Does a positive result mean I definitely have a milk allergy?
Is the RAST test the same as a skin-prick test?
Can this test explain lactose intolerance?
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