Biomarker: F078-IgE Casein

Overview

F078-IgE Casein measures immunoglobulin E (IgE) antibodies directed against casein, the major protein group in cow’s milk, also known as the Bos d 8 allergen component. Elevated levels indicate sensitization to casein and may support evaluation of IgE-mediated cow’s milk allergy, particularly when interpreted with the clinical history. A low or undetectable result makes casein sensitization less likely but does not exclude all forms of cow’s milk allergy. The test is clinically useful as an adjunct to history, skin testing, and, when necessary, a medically supervised oral food challenge; a positive result alone does not establish clinical allergy or predict reaction severity.

Clinical Use Cases

Supporting evaluation of suspected IgE-mediated cow’s milk allergy.
Assessing sensitization to the casein component of cow’s milk.
Supporting risk assessment for reactions to baked milk in individuals with cow’s milk allergy.
Supporting assessment of persistent cow’s milk allergy and likelihood of developing tolerance over time.
Providing component-resolved information alongside whole-cow’s-milk-specific IgE, particularly when clinical history and initial testing are inconclusive.
Contributing to research on cow’s milk allergy diagnosis, prognosis, and oral food challenge outcomes.

Specimen Types

Venous blood.
Serum, typically obtained from separated venous blood.

Measurement Methods

Quantitative serum allergen-specific IgE immunoassay.
Fluorescence enzyme immunoassay or comparable automated solid-phase immunoassay.
Component-resolved diagnostic assays targeting casein, generally reported in kUA/L or equivalent units.
Skin-prick testing with a casein or cow’s-milk extract may evaluate sensitization but is not the same measurement as serum F078-IgE.
Oral food challenge is a clinical diagnostic procedure used when needed to determine whether sensitization corresponds to clinical allergy; it does not measure F078-IgE.

Test Preparation and Influencing Factors

Fasting is generally not required for an allergy blood test.
Patients should report all medications and supplements to the ordering clinician.
Antihistamines usually do not affect serum-specific IgE testing, but they may affect skin-prick testing. Medication instructions should come from the healthcare professional.
Medications should not be stopped without medical direction.
Results should be interpreted with the timing, type, and reproducibility of symptoms after cow’s-milk exposure.
A positive result indicates sensitization, not necessarily symptomatic allergy.
The measured concentration does not reliably predict the severity of a future reaction.
Reference ranges, analytical platforms, reporting units, and decision thresholds may differ between assays.
Total IgE, age, eczema, and other atopic conditions can influence interpretation of specific-IgE results.
Broad food-allergen panels can produce clinically irrelevant positive results; testing is best targeted to foods implicated by the clinical history.
Non-IgE-mediated cow’s-milk reactions may occur despite a negative casein-specific IgE result.
Oral food challenges, when clinically indicated, should be performed under appropriate medical supervision because reactions can be severe.