23287 Allergen, Peanut, IgE (PEAN)

Establishing a diagnosis of an allergy to peanut

Defining the allergen responsible for eliciting signs and symptoms

Identifying allergens:

-Responsible for allergic disease and/or anaphylactic episode

-To confirm sensitization prior to beginning immunotherapy

-To investigate the specificity of allergic reactions to insect venom allergens, drugs, or chemical allergens

HIGHLIGHTS:

Immunoglobulin E antibody to total peanut extract will be tested.

In vitro serum testing for IgE antibodies to total peanut extract provides an indication of potential immune response to peanut related allergens that may be associated with allergic disease.

Results from peanut specific IgE antibody testing must be interpreted in the context of patient's clinical evaluation and history of allergen exposures.

Negative results for IgE to total peanut and any peanut components do not completely exclude the possibility of clinically relevant allergic responses upon exposure to peanut. Clinical correlation of results from in vitro IgE testing with patient history of allergic or anaphylactic responses to peanut is recommended.

Positive results for IgE to total peanut or any peanut components are not diagnostic for peanut allergy, and only indicate patient may be sensitized to peanut or a cross-reactive allergen. Recommend correlation of results from in vitro IgE testing with patient history of allergic or anaphylactic responses to peanut.

Testing for IgE antibodies may not be useful in patients previously treated with immunotherapy to determine if residual clinical sensitivity exists, or in patients in whom the medical management does not depend upon identification of allergen specificity.

Some patients with significantly elevated concentrations of total peanut IgE antibodies do not have any reaction when administered a peanut oral food challenge. This may be due to the presence of an IgE antibody specific for a nonallergenic protein present within the peanut extract.

Furthermore, some individuals with clinically insignificant or no sensitivity to allergens may have detectable levels of IgE antibodies in serum; therefore results must be interpreted in the clinical context. False-positive results for IgE antibodies may occur in patients with markedly elevated serum IgE (>2,500 kU/L) due to nonspecific binding to allergen solid phases.

Detection of IgE antibodies in serum (Class 1 or greater) indicates an increased likelihood of allergic disease as opposed to other etiologies and defines the allergens that may be responsible for eliciting signs and symptoms.