Medical Definition of Test, allergy scratch
Test, allergy scratch: Test done on the skin to identify the allergy substance (the allergen) that is the trigger for an allergic reaction.
A small amount of the suspected allergy-provoking substance is placed on the skin. The skin is then gently scratched through the small drop with a special sterile needle.
If the skin reddens and, more importantly, if it swells, then the test is read as positive and allergy to that substance is considered probable.Source: MedTerms™ Medical Dictionary
Last Editorial Review: 7/1/2016
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