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Milk-Specific IgE Radioallergosorbent Test (RAST), Qualitative, Serum — Deprecated

Published: August 9, 2026Updated: August 17, 2026

A legacy blood test that detects IgE antibodies to milk. A positive result suggests milk sensitization but does not by itself confirm clinical milk allergy.

Quick summary

["A positive result indicates antibodies to milk, which must be interpreted alongside symptoms and other allergy evidence."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
15846-9
Short code
Deprecated Milk IgE RAST Ql
Synonyms
Deprecated 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 blood test looks for milk-specific IgE antibodies, which are part of the immune response to milk proteins. It is a qualitative, legacy RAST test and may also be listed as deprecated, meaning newer laboratory methods may be used instead.

Why might I need this test?

Milk-specific IgE testing may be used when a patient has symptoms such as hives, swelling, wheezing, vomiting, or digestive discomfort after eating milk. It can also be used as part of an evaluation for suspected cow's-milk protein allergy, particularly in infants and children.

How is the test performed?

A blood sample is collected and analyzed for IgE antibodies directed against milk proteins. This legacy test generally reports whether milk-specific IgE is detected rather than providing the quantitative measurement used by many current assays.

How do I prepare for the test?

No fasting or special preparation is usually required. Tell your clinician about food reactions, current diagnoses, medications, and supplements so the result can be interpreted in context; do not stop prescribed medicines without medical advice.

Reference range

Adult: 10-40 U/LN/A

Specimen: serum

No special preparation required. Avoid fatty meals before the test if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Milk-specific IgE test

Frequently asked questions

Does a positive result mean I have a milk allergy?
Not necessarily. It shows that milk-specific IgE antibodies are present, indicating sensitization; clinical symptoms and sometimes an oral food challenge are needed to confirm a true allergy.
Is this the same as a lactose intolerance test?
No. Milk-specific IgE testing evaluates an immune reaction to milk proteins, while lactose intolerance results from difficulty digesting the milk sugar lactose.
Why was this RAST test marked deprecated?
It is a legacy qualitative test and may not be available from all laboratories. Current clinicians often use a quantitative milk-specific IgE assay instead, interpreted according to the laboratory's method and clinical context.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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