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Cow’s Milk Immunoglobulin G (IgG) in Serum or Plasma

Published: August 9, 2026Updated: August 16, 2026

This test measures the presence of antibodies (specifically Immunoglobulin G, or IgG) your body produces in response to cow’s milk proteins.

Quick summary

["Helps assess potential allergies or immune reactions to cow’s milk."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
6729-8
Short code
Cow Milk IgG Qn
Synonyms
Cow Milk IgG Qn
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82784
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 Does This Test Measure?

IgG antibodies are part of your immune system’s defense. When your body encounters cow’s milk proteins (like casein or whey), your immune system may produce IgG antibodies as part of an immune response. This test checks the level of these antibodies in your blood.

Why Might You Need This Test?

Doctors may order this test if you have symptoms like rashes, digestive issues, or persistent problems after consuming cow’s milk, even if you’re not sure if it’s causing them. It can also help diagnose or monitor certain conditions related to food allergies or sensitivities.

How Is the Test Performed?

A small blood sample is taken from a vein in your arm. The blood is then processed to separate serum or plasma, which is tested for IgG antibodies against cow’s milk proteins using an immunoassay method.

What Are Possible Results?

Results may indicate a normal immune response, a mild sensitivity, or a higher-than-normal level of antibodies, which could suggest an allergy or immune reaction. However, results alone don’t confirm a diagnosis—your doctor will consider symptoms and other tests.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Elevated IgG levels to cow’s milk may suggest an allergic or sensitized immune response, which can sometimes lead to symptoms like hives, stomach pain, or breathing difficulties. While IgG alone doesn’t always mean you’re allergic, it can guide further testing or dietary adjustments. Always discuss results with your healthcare provider.

Short name

IgG Antibody to Cow’s Milk

Frequently asked questions

What Does a Positive or High Result Mean?
A high IgG level to cow’s milk may indicate your immune system is reacting to the proteins, which could mean you’re more likely to have symptoms when consuming cow’s milk. This doesn’t always mean you’re allergic, but it may warrant further evaluation, such as elimination diets or skin prick tests.
Can This Test Be Used to Confirm a Cow’s Milk Allergy?
No, this test alone cannot confirm a cow’s milk allergy. IgG antibodies are part of your immune system’s general response, not specifically an allergy. Allergies are typically diagnosed through other tests like skin prick tests or elimination diets, which your doctor may recommend.
How Often Should I Get This Test?
The frequency depends on your symptoms and medical needs. Your doctor may recommend retesting if symptoms change or if you’re undergoing treatment for suspected allergies or sensitivities. Follow their guidance closely.
  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 16, 2026. · Read our editorial policy