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Diagnosing Allergies: Blood Test vs. Skin Testing

Diagnosing Allergies: Blood Test vs. Skin Testing

About 50 million people in the United States experience allergies in any given year, and anything from airborne pollen to sesame seeds can trigger them. The best way to figure out whether you or a loved one has joined this group is by having us test for allergies.

As the name of our practice  — Advanced ENT & Allergy — implies, our team, which includes Dr. Timothy Queen, Nancy Gibson, FNP-BC, and Kristi Pham, MSN, FNP-BC, specializes in the diagnosis and treatment of allergies of every kind.

When it comes to testing for allergies, there are several ways we can go about it, and we discuss those methods and why we might choose one over the other here.

Different types of allergy testing

First, let’s take a look at the different types of tests that we offer:

Skin prick tests

Also called a scratch test, we make very small punctures of scratches in your skin, usually on your arm or back, and introduce allergens to the disturbed area. We can introduce 10-50 potential allergens; if you’re allergic, your skin should react within 15-20 minutes.

Intradermal testing

We inject the allergen directly into your skin.

Patch test

With this type of testing, we’re looking for a specific reaction called contact dermatitis. To conduct a patch test, we place the allergens directly onto your skin and then cover it with a patch that you wear for up to three days. When you come back, we check for a reaction.

Blood test

We draw a sample of your blood and check for specific antibodies called immunoglobulin E.

Deciding which test is right for you

Before we conduct any testing, we perform a thorough review of your health, as well as your symptoms, and this information guides our search.

For example, if you react to certain foods, we narrow down our search to potential food allergens. Or, if you’re experiencing watery eyes and sneezing during certain times of the year, we search for seasonal allergens like pollen.

Once we know what allergens to use in the allergy test, our next step is to figure out which test is best. In most cases, we prefer skin testing because it’s accurate and quick. We typically start with the scratch test, but if the test is inconclusive, we may try intradermal testing or a patch test.

We recommend blood testing when we’re concerned about a severe reaction to an allergen. With a blood test, we don’t expose you directly to the allergen but look for evidence of an allergy indirectly in your antibodies.

Another consideration is that if you take allergy medications, you need to stop taking them for a few days before your skin testing. If you’d prefer to stay on your medications, we can turn to a blood test.

Lastly, if you have a severe rash on your body, perhaps due to eczema or psoriasis, we might not be able to conduct a skin test, so we turn to blood testing.

The best way to figure out whether you need allergy testing and which type is to come see us. To get started, simply contact our office in Newport News, Virginia, to schedule a consultation.

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