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Alpha-Lactalbumin–Specific IgA Antibody, Qualitative

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

A qualitative blood test that detects IgA antibodies to alpha-lactalbumin, a cow’s-milk protein sometimes used when evaluating cow’s milk protein allergy.

Quick summary

["A positive result may indicate an immune response to alpha-lactalbumin, but it must be interpreted alongside symptoms and other allergy testing."]

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

Key facts at a glance

LOINC
25453-2
Short code
A-Lactalb IgA Qn
Synonyms
A-Lactalb IgA Qn
Category
liver
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 is this test?

This test checks a blood sample for IgA antibodies directed against alpha-lactalbumin, a protein found in cow’s milk. It is reported as positive, negative, or sometimes indeterminate.

Why might I need this test?

It may be ordered when a patient has symptoms suggesting cow’s milk protein allergy, particularly digestive, skin, or respiratory reactions after milk exposure. Results are considered together with the medical history, physical examination, and other allergy tests.

How is the test performed?

A blood sample is analyzed in the laboratory to determine whether alpha-lactalbumin-specific IgA antibodies are detectable. This is a qualitative test and does not provide a precise antibody concentration.

How do I prepare for the test?

Fasting is usually not required. Tell your clinician about current milk or dairy exposure, recent blood transfusions, immune disorders, and any medicines or supplements that could affect the results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Alpha-Lactalbumin IgA Antibody

Frequently asked questions

Does a positive result confirm cow’s milk protein allergy?
No. It shows that alpha-lactalbumin-specific IgA antibodies are present, but allergy is diagnosed using the overall clinical picture and other testing when needed.
Can I continue eating dairy if the result is negative?
A negative result does not by itself prove that all milk products are safe. Discuss any suspected food reaction and avoidance plan with your clinician or allergist.
What if I have a low or absent IgA level?
Alpha-lactalbumin IgA antibody results may be unreliable or falsely negative when total IgA is very low or absent. Your clinician may recommend total IgA measurement or another type of allergy testing.
  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