RAST test: allergy blood tests explained
Last updated: 17 January 2017
What is an allergy blood test?
An allergy blood test (radioallergosorbent or RAST test) may be requested when a specific allergy is in question.
The test gives an indication of antibodies to a specific trigger antigen, such as pollen or house-dust mite.
When would you need a RAST test?
Your doctor may request a RAST test in the event of severe allergy, asthma or hayfever, where the precipitating substance (known as an antigen) is not clear.
A subgroup of antibodies called IgE antibodies are strongly associated with the abnormal immune system response in allergic reactions.
Amongst these IgE antibodies, allergen-specific IgE antibody numbers can be measured by the RAST test.
How is a RAST test performed?
A radioallergosorbent test is a blood test and requires a blood sample from a vein.
RAST test results explained
RAST test results are given in terms of an antibody titer.
- Differential white cell count (Diff)
- Respiratory function tests (RFTs)
- Peak expiratory flow Rate (PEFR)
Also known as
- Radioallergosorbent test
- Allergy screen
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This article is for informational purposes only and should not be taken as medical advice. If in doubt, HealthEngine recommends consulting with a registered health practitioner.