Biomarker: F076-IgE Alpha Lactalbumin

Overview

F076-IgE Alpha Lactalbumin measures immunoglobulin E (IgE) antibodies directed against bovine alpha-lactalbumin, also known as Bos d 4, a whey protein in cow’s milk. Alpha-lactalbumin contributes to lactose synthesis in milk and can act as an allergen in individuals with IgE-mediated cow’s milk allergy. A detectable result indicates sensitization to alpha-lactalbumin but does not, by itself, establish clinical allergy or predict reaction severity. The test is clinically useful as part of component-resolved allergy assessment, interpreted with the clinical history and, when appropriate, supervised oral food challenge.

Clinical Use Cases

Assess sensitization to a specific cow’s-milk protein in patients being evaluated for possible IgE-mediated cow’s milk allergy.
Complement testing for whole cow’s-milk-specific IgE and other milk components, including caseins and beta-lactoglobulin.
Support component-resolved diagnosis by identifying an individual’s pattern of milk-protein sensitization.
Contribute to evaluation of patients with immediate symptoms after consuming cow’s milk or milk-containing foods.
Support research on allergen recognition and clinical patterns of cow’s-milk sensitization.
Help guide, but not replace, decisions about dietary elimination, reintroduction, or medically supervised oral food challenge.

Specimen Types

Serum obtained from venous blood is the typical specimen for measurement of allergen-specific IgE.
Plasma may be accepted by some validated laboratory methods, depending on laboratory requirements.

Measurement Methods

Automated in-vitro allergen-specific IgE immunoassay using purified native or recombinant alpha-lactalbumin.
Enzyme-linked immunosorbent assay (ELISA), used in clinical research studies to measure alpha-lactalbumin-specific IgE.
Component-resolved diagnostic assays that quantify IgE against individual allergenic proteins, reported commonly in kUA/L or equivalent standardized units.
Results should be interpreted according to the assay-specific calibration, reference intervals, and clinical laboratory reporting system.

Test Preparation and Influencing Factors

Fasting is generally not required for serum-specific IgE testing.
Antihistamines generally do not affect blood specific-IgE results, although they may affect skin-prick testing.
A positive result demonstrates IgE sensitization and does not confirm symptomatic food allergy or predict reaction severity.
Results may be influenced by age, atopic conditions, current or previous exposure, and the patient’s broader pattern of sensitization.
Clinical history, physical examination, and testing for whole milk and other milk components are important for interpretation.
If the diagnosis remains uncertain, a medically supervised oral food challenge may be required; it is the reference approach for confirming or excluding food allergy.
Testing should be interpreted using the laboratory’s assay-specific thresholds because cutoffs are not universally diagnostic for cow’s-milk allergy.