Biomarker: W020-IgE Nettle

Overview

W020-IgE Nettle measures serum immunoglobulin E (IgE) antibodies directed against nettle, generally referring to Urtica dioica pollen or extract. IgE is an antibody involved in immediate-type allergic reactions, and detectable nettle-specific IgE indicates immunologic sensitization to the tested allergen. A positive result may support nettle-related allergic rhinitis or other immediate hypersensitivity when consistent symptoms occur after exposure, but it does not by itself confirm clinical allergy or predict reaction severity. Nettle-specific IgE testing can help identify a suspected inhalant allergen and guide clinical evaluation alongside medical history and physical examination.

Clinical Use Cases

Evaluation of suspected allergic rhinitis, conjunctivitis, or respiratory symptoms associated with nettle exposure.
Identification of sensitization to nettle pollen when exposure history suggests a seasonal or occupational relationship.
Supplementary testing when skin-prick testing is unsuitable because of extensive skin disease, interfering medications, or other clinical considerations.
Research characterization of nettle-pollen sensitization and IgE-mediated responses. Human clinical reports of nettle allergy are limited, and nettle pollen is generally considered less allergenic than some related pollens.
Assessment of sensitization as part of a targeted inhalant-allergen panel. Testing should be guided by the clinical history rather than performed as an indiscriminate screening panel.

Specimen Types

Venous blood serum.
Capillary blood-derived serum may be acceptable for some validated laboratory methods.
Skin-prick testing with a standardized nettle allergen extract is an alternative in vivo assessment of sensitization, but it is not the same specimen-based measurement as serum-specific IgE testing.

Measurement Methods

Enzyme-linked or fluorescence-based immunoassays for allergen-specific serum IgE.
Solid-phase immunoassays, including modern nonradioactive RAST-type methods.
Radioallergosorbent testing, or RAST, an older method for detecting allergen-specific IgE in blood.
Skin-prick testing with nettle extract, which measures an immediate wheal-and-flare response rather than serum IgE concentration.
Research methods may include immunoblotting, nasal provocation, and basophil activation testing in selected clinical investigations of nettle allergy.

Test Preparation and Influencing Factors

Fasting is generally not required for a specific-IgE blood test, although the ordering laboratory or clinician may provide different instructions.
No special patient preparation is required for some serum-specific IgE collection protocols.
Antihistamines generally do not interfere with the analytical measurement of serum-specific IgE, but they can suppress responses during skin-prick testing. Medication instructions should therefore be confirmed with the clinician, particularly when both blood and skin testing are planned.
A positive result indicates sensitization, not necessarily clinically relevant allergy. Interpretation should incorporate exposure timing, symptoms, physical examination, and medical history.
The measured specific-IgE concentration does not reliably predict the severity of a future reaction.
False-positive results can occur, including from cross-reactive antibodies or clinically irrelevant sensitization.
Results may vary between allergen extracts, assay platforms, and laboratories; results from serum testing and skin-prick testing are not fully interchangeable.
Smoking, parasitic infection, and other causes of increased total IgE may affect overall IgE interpretation but do not specifically establish nettle allergy.