We are pleased to announce from 25th May 2021 a new Allergy tab in eclair e-ordering to assist in selecting the appropriate allergy tests for your patients.
Here you will find both Skin Prick Testing and EAST Specific IgE Allergen testing options.
It is expected that these testing groups will cover off the majority of primary care allergen testing requirements.
Other Allergens are still available to be selected and will create a popup to list required allergens. Please list these in order of testing priority, to ensure we can more easily deal with small samples and get feedback on what are the most likely causative allergens.
The allergy ordering tool will allow you to select the appropriate clinical situation and the appropriate tests to order. It will also allow you to supply further clinical details which will assist both our scientists and pathologists in interpreting the results.
There are relatively few clinical situations where allergy testing is clinically helpful. These include:
- Allergic rhinitis, asthma (some cases), Eczema (limited cases), order aeroallergens (for example house dust mite, pets, and pollens) only, particularly where aeroallergen immunotherapy is being considered
- Food allergy, only where there is a history of an anaphylactic or acute urticarial reaction related to that food being ingested and the patient continues to avoid the food in question
- Venom allergy, where the patient has had a generalised reaction to an insect sting and the patient is looking to consider venom immunotherapy through a specialist
Allergy testing is NOT helpful in:
- Irritable bowel related symptoms and food aversions/intolerances where the reported symptoms related to food is not clearly IgE mediated
- Where the food is currently being eaten
- Allergic reactions to insect stings that are localised and not generalised as venom immunotherapy is not indicated unless there has been a generalised reaction such as anaphylaxis.
- Specific IgE testing to penicillins and cefaclor, as these tests have a poor sensitivity and specificity particularly where the reaction is greater than 6 month ago. For more information on penicillin allergy see https://www.allergy.org.au/members/ascia-penicillin-allergy-guidelines
Guidelines for ordering allergy testing
- Skin prick testing is usually preferred over specific IgE testing and in most situations DO NOT ORDER BOTH.
- Specific IgE testing is preferred over skin prick testing in the following situations:
- Where skin prick testing is not available either due to the location of the patient or due to the allergen in question not being available for skin prick testing
- Where the patient cannot cease taking antihistamines for three days
- Where there is significant dermographism
- Only order the allergens you need to assist in a diagnosis or where the result will alter management. Positive allergy tests (sensitisation) occur commonly where there is no true allergy, particularly in patients with eczema. This situation can lead to patients avoiding foods and other allergens that they should not
- Negative allergy testing does not rule out all significant IgE mediated allergic reactions. This is particularly true for specific IgE testing. Always be guided by the history from your patient
- There is no level of specific IgE that will differentiate between a patient with or without an allergy to the substance being tested. Although the cut-off for the current assay is arbitrarily set at 0.35kU/l, clinically significant sensitisation can occur at lower level down to 0.1kU/l
We welcome feedback regarding the new allergy test selection, and we hope that it improves the care of your patients. For any queries please email pathologist@wellingtonscl.co.nz
Richard Steele, Medical Director Wellington SCL, Immunopathologist
Paul Tustin, HOD Immunology, Wellington SCL
Click here to download and print the Guidelines as PDF
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