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Milk Protein (Casein) Concentration

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

This test measures the amount of casein protein in your milk. Casein is a major protein found in dairy products and plays a role in milk’s structure and nutritional value.

Quick summary

["Understanding your milk protein levels can help assess dietary needs or potential allergies."]

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

Key facts at a glance

LOINC
102430-6
Short code
Mare Milk IgE RAST
Synonyms
Mare Milk IgE RAST
Category
chemistry
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
Method
rast
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 Casein?

Casein is a group of related proteins found primarily in cow’s milk. It makes up about 80% of the total protein in milk and is responsible for its creamy texture and ability to form curds when coagulated (e.g., during cheese-making).

Why Might You Need This Test?

This test may be ordered if you’re being evaluated for milk protein allergies, lactose intolerance, or if your diet includes milk products. It can also help monitor milk production or nutritional composition in clinical settings.

How Is the Test Performed?

A sample of your milk is collected (e.g., from breast milk, cow’s milk, or other dairy sources). The sample is then analyzed using a specialized laboratory method to measure casein concentration.

What Do Results Mean?

Results provide a quantitative measure of casein in your milk sample, but interpretation depends on clinical context (e.g., whether it’s for allergy screening, nutritional assessment, or research). Your healthcare provider will discuss findings with you.

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

Casein in Milk

Frequently asked questions

Why would my doctor order this test?
Your doctor may recommend this test if you have symptoms like digestive issues, allergic reactions, or if you’re being evaluated for milk protein-related conditions. It may also be used in specialized settings like lactation clinics or research studies.
What are typical reference ranges for this test?
Reference ranges vary by source and may differ for breast milk versus cow’s milk. Your results will be compared to standards specific to your sample type and clinical context. Your provider will explain what your numbers mean for you.
Can I prepare for this test?
No special preparation is needed for this test. Simply provide a sample of your milk as directed by your healthcare provider. If testing breast milk, ensure you’re not on medications that might affect protein levels.
  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