If the skin test is negative, a person may be told they don't require allergy shots and don't have to worry about another severe reaction. However, a study in the May issue of the Journal of Allergy and Clinical Immunology finds that even if one test is negative, you still may be at risk for a severe reaction. In a study, led by Golden, researchers looked at 99 people who had had a systemic reaction to an insect sting but had a negative reaction to the insect venom skin test. They found that in about a third of those people, further blood tests showed positive responses to insect venom. While the skin test is the gold standard, it is not perfect.
Some people are positive on the skin test, some on the blood test.
You should still get a skin test, but consider the blood test as complementary, and get that, too. Bielory is director of the Asthma and Allergy Research Center of the New Jersey Medical School, in Newark. The main message is that one test is not enough, Golden says. If someone thinks he may be allergic to insect stings, but a skin test is negative, it's a good idea to get a blood test. If that is negative, wait 6 months and get another skin test.