Other Health Tests
What Happens During the Test?
In adults, the test is done on the forearm; in children it's done on the upper back. (The child disrobes from the waist up and lies on his or her stomach.)
Your doctor decides what allergies are to be tested for. Some people are tested for as many as a few dozen at one visit. Individual drops of fluid are dripped in rows across the skin. The doctor uses a needle to make small light scratches in the skin under each drop, to help the skin absorb the fluid. The scratches aren't deep enough to cause bleeding. Each drop contains proteins from a separate allergen (a substance, like ragweed pollen, that triggers allergy symptoms).Your doctor notes where each drop of fluid was placed, either by keeping a chart or by writing a code on the area of skin being tested.
For many people, the most difficult part of this test is next: You need to stay still long enough (usually about 20 minutes) to give the skin time to react. Your skin might tickle or itch during this time, but you won't be allowed to scratch it. At the end of the waiting time, your doctor will examine each needle scratch for redness or swelling.
Page 3 of 6 Next Page: Scratch Test for Allergies Risks
From Health A-Z, Harvard Health Publications. Copyright 2007 by the President and Fellows of Harvard College. All rights reserved. Written permission is required to reproduce, in any manner, in whole or in part, the material contained herein. To make a reprint request, contact Harvard Health Publications. Used with permission of StayWell.
You can find more great health information on the Harvard Health Publications website.