How Does an Allergy Test Work?

To order any of our allergy tests, please email info@gtldna.com.au with your requested test and telephone number.

From a small amount of blood, we can  measure the levels of the allergy antibody IgE that is produced when blood is mixed with a series of allergens. For a total list of allergies that we can test for and the prices, please click the below button:

List of Allergies Tested

How exactly does the blood test work?

The test is ideal for detecting an allergy in an individual and it requires just a medical blood draw. The test is a so called Specific IgE (sIgE) Blood Test (sometimes also referred to as RAST or ImmunoCAP testing). IgE stands for immunoglobulin E and the test measures the levels of immunoglobulin E in the blood sample. Immunoglobulin E is an antibody, produced by our immune system, which like other antibodies, is produced in response to different allergens, such as bacteria, fungal spores or any other type of substances perceived as a threat. Once the threat is perceived in the body, a release of chemicals such as histamines is triggered. The IgEs are allergen-specific, which means that different variants of IgE are produced as a response to different allergens. Increased levels of IgE that are specific for the particular substance of interest (for example cat hair/dander or house mold) in the blood sample indicates an allergy to that particular substance. This means that the IgE variant found in cases of a cat hair allergy will be different to the IgE variant in the case of a dust mite allergy.

Is the test safe?

Yes, this type of allergy test using a blood draw is far less risky than a skin prick test which could have very serious complications, if not fatal, in individuals (especially children) who can have a life-threatening reaction in response to the allergens which are directly introduced in skin prick tests. There are no risks with the test we offer. The only issues can be due to the medical blood draw which could leave some individuals feeling faint, bruising etc.

Will the test always provide positive results if I am really allergic to something?

IgE levels tend to rise when exposure is high and can dwindle when there has been no exposure. For example, in cases of an allergy to pollen, we would expect IgE levels to increase around spring but decline later on in the year when pollen levels in the air also decline. If a person is allergic to something they are persistently exposed to, perhaps a house pet, then IgE levels would likely be persistently high.

Do I need a specialist?

The test will usually be recommended if you have persistent symptoms that could indicate an allergy. The most common symptoms typically affect the respiratory tract, digestive system, eyes or skin but other parts of the body could be affected.

In order to direct you to this test, your specialized will need an indication that the symptoms are due to an allergy:

 

  • Ask detailed questions about signs and symptoms
  • Perform a physical exam
  • Have you keep a detailed diary of symptoms and possible triggers

The results of an allergy test are best interpreted by a specialist and we require that this test be ordered by your specialist.

Dealing with allergies

For more information about how to live with allergies, common allergies, remedies and more such general information, visit our article on Living with Allergies, Treatments and Common Allergies.

Note: Your only additional cost will be the blood collection fee that should be arranged with the sample collector during your pathology appointment


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