Allergy Blood Tests
Blood tests are useful when the skin tests are not practical due to extensive eczema, or if the patient cannot stop antihistaminic drugs that block skin tests, or if the patient has high risk of anaphylactic shock if skin test is attempted. Blood tests can also be used to confirm skin prick test results, or before a food challenge test is performed.
There are four main types of allergy blood tests.
|There are four main types of allergy blood tests.|
|Total IgE: this measures all IgE in the blood which reflects your total allergic potential.|
|Specific IgE (Immune cap test, previously known as a RAST): this measures the amount of IgE to a specific pollen, dust mite, animal dander, food or drug.|
|Component resolved IgE testing: also known as component resolved diagnosis (CRD) – this is a very recent development in specific IgE testing, whereby the laboratory can detect IgE to specific pieces of an allergen. Some food allergens, such as peanut, a positive CRD to a particular part of the peanut protein may be more likely to indicate allergy rather than just sensitisation.|
|IgG blood tests for delayed food allergy is an emerginc concept. Orthodox allergy specialists think this test is controversial. But new approaches popularized by Dr Mark Hyman and Dr Oz makes our patients seek these tests. In our experience, IgG test does have a value in guiding allergy and weight loss.|