When it comes to allergy testing, there can be a lot of confusion. How does allergy testing work? Is it accurate? Does it matter what type of testing is done? These questions, and many more, can be hard to get straight answers to. This article aims to clear up some of the common questions when it comes to allergy testing. First, let’s define what allergy testing is.
What Is Allergy Testing?
Allergy testing is the process of testing a person’s response to different substances, called allergens. Allergens are things like dust, grass, trees, foods, or anything else that might be causing your allergy symptoms. By measuring your response to the allergens, a treatment can be made to help lessen or eliminate your allergic reactions. However, there are several different methods of allergy testing and they are not all created equal.
Different Types of Allergy Testing:
Prick (or scratch) testing
Prick testing is also sometimes called scratch testing, or Skin Prick Testing (SPT). It is the simplest form of skin testing and is relatively inexpensive. It is the most common type of allergy testing and is the method most primary care doctors use. It is performed by placing a drop of an allergen on the skin, and then scratching or pricking the area with a needle, scalpel, or plastic probe. The scratch allows the allergen to enter the skin and cause a reaction. The doctor then examines the area to determine if you are allergic to the allergen. Usually, a white bump or red circle means you are allergic to the allergen. Prick tests don’t usually give false negatives, meaning it won’t say you aren’t allergic to something when you really are allergic. However, prick test DO produce a very large number of false positives, meaning the test will say you are allergic to something when you really aren’t. According to www.foodallergy.org, 50%-60% of prick tests produce false positives.
Patch testing
Patch testing involves putting multiple allergens on the back or forearm at once using patches. The patches are left on the skin for 48 hours and then removed to examine the skin for allergic reactions. During the 48 hours, you cannot shower, swim, or do anything that would cause you to sweat heavily. Patch testing can be beneficial in diagnosis delayed allergic reactions that take several days to appear.
Blood testing
Blood testing, sometimes referred to as an immunoassay test, is probably the easiest form of allergy testing. It involves a normal blood draw, and then the blood is tested for certain antibodies to determine if you are allergic to certain substances. Blood testing works better for food allergies rather than dust, tree, or mold allergies.
Intradermal (under the skin) testing
Intradermal testing involves injecting a small amount of an allergen under the skin with a small needle. The injection creates a small bubble on the surface of the skin that is measured immediately after the injection, and then again after a set amount of time, usually 5-10 minutes. Multiple allergens can be injected at once, or one at a time. For more accurate results, the allergens can be diluted into multiple concentrations to determine how allergic the patient is to certain allergens.
What’s The Best Type Of Allergy Testing?
Determining the best type of allergy testing is dependent on each patient’s circumstances. For example, many kids can’t handle intradermal testing, or even scratch testing, so blood testing may be the best solution. However, if someone is having severe allergic reactions, blood testing may not be accurate enough. The patient would likely need intradermal testing, which would be more accurate and would help avoid causing any adverse reactions during testing because the testing can start with less concentrated allergens. Another thing to keep in mind is the cost. Most insurances will cover prick testing and intradermal testing as long as it stays within certain criteria. Blood testing and patch testing may not be covered unless it’s determined to be medically necessary. For those without insurance, it can be difficult to get a specific cost for allergy testing, but in general it will be between $300 and $1000, depending on the type of testing, amount of allergens, and the doctor who is doing the testing.
Allergy Testing Ranked By Accuracy (In our opinion)
- Intradermal testing (most accurate)
- Blood testing
- Prick testing
- Patch testing
Allergy Testing Ranked By Cost (In general. There’s a great deal of variance)
- Blood testing $200-$500
- Prick testing $300-$800
- Intradermal testing $300-$1000
- Patch testing $400 – $1200
Our advice?
Intradermal testing is probably the way to go, unless you have mild symptoms and just want a little relief. In that case, prick testing or blood testing is probably the most practical option.