A RAST test for skin is a blood test that measures the amount of IgE antibodies in your blood that are specific to allergens that cause skin reactions. This test is used to diagnose allergies, particularly those that cause eczema, hives, or other skin problems.
How does a RAST test work?
The RAST test works by mixing a small amount of your blood with a known allergen. If you are allergic to that allergen, your blood will contain IgE antibodies that will bind to the allergen. The amount of IgE antibodies that bind to the allergen is measured, and this result is used to determine if you are allergic to that allergen.
What are the benefits of a RAST test?
- Accurate: RAST tests are generally accurate in identifying allergies.
- Safe: It's a non-invasive test that doesn't involve skin pricking.
- Convenient: It's a simple blood test that can be done at a doctor's office or laboratory.
When is a RAST test used?
A RAST test is used when a doctor suspects you have an allergy that causes skin reactions. It can help diagnose:
- Atopic Dermatitis (Eczema): A common skin condition characterized by itchy, red, and inflamed skin.
- Urticaria (Hives): A skin reaction that causes itchy, red welts.
- Contact Dermatitis: A skin reaction caused by contact with an allergen.
What are the limitations of a RAST test?
- Not 100% accurate: It may not always detect all allergies, especially mild ones.
- May not be helpful for all skin conditions: It may not be useful for diagnosing other skin conditions that are not caused by allergies.
- May not be available for all allergens: It may not be available to test for all possible allergens.
What should you do if you think you have a skin allergy?
If you suspect you have a skin allergy, it is important to see a doctor for diagnosis and treatment. They will be able to determine if a RAST test is appropriate for you.
