Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (665 page)

   Clinical performance of specific IgE-based serum allergen tests typically has sensitivity ranging from 84% to 95% and specificity ranging from 85% to 94%.

   Various types of specific panels, mixes, as well as specific allergen tests currently performed at various labs and contact your lab for details.

Normal range:

   Use

   To establish the diagnosis of an allergic disease and to define the allergens responsible for eliciting signs and symptoms

   To identify allergens that may be responsible for allergic disease and/or anaphylactic episode and to confirm sensitization to particular allergens prior to beginning immunotherapy

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

   Interpretation

Increased In

   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.

Decreased In

   NA.

   Limitations

   The demonstration of sensitization is not sufficient to diagnose an allergy, however, because a sensitized individual may be entirely asymptomatic upon exposure to the allergen in question. Thus, allergy tests must be interpreted in the context of the patient’s specific clinical history, and the diagnosis of an allergic disorder cannot be based solely on a laboratory result.

   If the result is markedly positive (e.g., a Class VI result), the history suggests a past reaction to the allergen, and the allergen is well characterized, then the diagnosis of an allergy can usually be made without further evaluation. If the result is weakly positive, then further evaluation is usually needed.