BLOOD TESTS for ALLERGIC SENSITISATION
In addition to skin prick tests it is possible to perform blood tests to detect allergic antibodies (IgE) that bind to specific allergens. These tests work by coating allergen proteins onto a surface, adding the patient’s blood then detecting IgE antibodies that have bound to the surface. Different systems are used including different detection systems, but a common test is the radioallergosorbent (RAST) test.
What are the advantages and disadvantages of RAST tests?
The advantage of blood tests is that a wider panel of test allergens is generally available and that these tests may be performed if the patient has skin diseases or has taken antihistamines. They are no more sensitive than skin prick tests and the disadvantages are that the result is not available immediately and the additional costs involved.