August 2026  |  Linda Armstrong & Luke Lemons |  ✓  Medically reviewed by: Gary Falcetano, PA-C, AE-C; Fabio Iachetti, MD; Eva Södergren, PhD, MSc 

A licensed Physician Assistant with more than 25 years of diverse experience in emergency and disaster medicine, primary care, and allergy and immunology, Gary Falcetano is the U.S. Clinical Affairs Manager for Allergy in ImmunoDiagnostics at Thermo Fisher Scientific. Fabio Iachetti is a licensed physician with more than 15 years of diverse experience in several disease areas such as allergy, CV, pain, GI, rheumatology, urology, and diabetology. He is a Senior Medical Manager for Allergy in ImmunoDiagnostics Global Medical Affairs at Thermo Fisher Scientific. A nutritionist by training, Eva Södergren now works as a Senior Scientific Advisor for Allergy on the Medical and Scientific Affairs team for Thermo Fisher Scientific’s ImmunoDiagnostics division.

Types of Blood Tests

Whole allergen and allergen component tests:

The two broad types of specific IgE blood tests with whole allergens and tests with allergen components. Paired with a symptom history and physical exam, whole allergen tests help your healthcare provider to determine if you’re sensitized to a specific allergen or group of allergens.

Meanwhile, testing with allergen components helps providers identify the specific molecules (e.g., proteins, carbohydrates, enzymes) that may cause reactions. Knowing which molecules you’re sensitized to may help your provider determine if there could be an increased risk for a severe systemic reaction.

Additionally, testing with allergen components might reveal to providers that you can tolerate an allergen in a specific form. For example, if you have an egg allergy, this testing may suggest that you’re likely to tolerate baked eggs but not lightly cooked or raw eggs. (That means you may be able to eat baked goods such as sweets, breads, and more.)

Similarly, component testing can help determine if you’re sensitized to a protein found only in male dogs, so you may be able to tolerate and have a female dog.¹

Allergy profile tests:

Allergy profile tests are developed by individual labs and are a combination of individual specific IgE blood tests, and they’re conducted with the same type of blood draw. They check for sensitizations to a number of allergens all at once (sometimes called a “panel”). For example, a common profile test is a respiratory allergen profile, which tests for sensitizations to a selection of allergens that we breathe in and that cause respiratory symptoms like congestion and sneezing.

This type of profile test checks for common indoor allergens like pet dander, dust mites and mold. It will also test for different types of pollen sensitizations. Respiratory allergen profiles can even be tailored to your geographic region so that they’re testing to see if you react to the types of pollen present in your area. If you live in a place where timothy grass, a common aeroallergen, doesn’t grow, there is no reason to test you for that allergen. A regionally localized respiratory profile focuses on the allergic triggers specific to where you live.

Food allergy profile tests are also available if your healthcare provider suspects you may have a food allergy and are used when it is difficult to pinpoint a specific food that is suspected to be causing your symptoms. These profiles test for a concise selection of the most common food allergens, and, if indicated, they also evaluate the individual proteins (allergen components) found within those food allergens. Understanding if you are sensitized to these specific proteins can provide valuable information that can help to determine whether or not you can tolerate egg or milk in a cooked form or not. They can also assist in identifying if you’re at high risk of a systemic reaction, say, from a peanut allergy.¹

Why these tests are important:

Allergy profiles are informative and efficient ways to help get the full picture of your allergic sensitizations. With this data, your healthcare provider can identify more specifically what you’re reacting to, including if it’s just a food in a certain form or a particular type of pet. These tests can also show cross-reactivity, or where a similar-shaped protein in a pollen and a food item could cause you to have a reaction.¹

Tests for multiple allergens at once can also reduce or even completely avoid the need for multiple blood draws or office visits. With more comprehensive information from a single specific IgE blood test, your healthcare provider can share relevant tips for avoiding your triggers and managing your symptoms better, and that can mean better quality of life without repeated tests.

When talking about blood tests with your healthcare provider, there is one important distinction to note: Those healthcare providers who have used blood tests for decades may be most familiar with the term radioallergosorbent test (RAST), which measures specific IgE but is actually a term for an older technology. In fact, it doesn’t represent modern specific IgE blood tests for allergies, and any literature about RAST likely doesn’t apply to current tests. 

Blood Tests vs. SPTs

Specific IgE tests and SPTs are frequently used to help diagnose allergies. But how do you and your healthcare provider choose between them? Here are some key differences followed by a handy chart to further highlight the comparison. 

• Testing Personnel. While rare, SPTs can cause life-threatening anaphylaxis.¹ Thus, SPTs typically must be administered and interpreted by allergy specialists, who are trained to deal with anaphylaxis, and in a facility that is capable of providing life-saving tactics and equipment.^2-3 Meanwhile, blood tests, which carry no risk of anaphylaxis, can be ordered by almost any healthcare provider and carried out via a blood draw in a clinic or perhaps a laboratory.⁴
• Speed to Diagnosis. SPT results are often obtained in less than an hour, and blood test results are usually back from the lab within a few hours to a few days.³ However, when you consider that it may take weeks to months to secure an appointment with a specialist—and that you may need to see a general practitioner first to get a specialist referral—a blood test may actually lead to a faster diagnosis.
• Comfort. With an SPT, the provider places allergen droplets on the skin and then scratches over them to get the allergen into your skin. Or, he or she uses a sharp device to prick your skin up to 50 times with different allergens.⁴ A blood test typically requires a single needle stick for a blood draw. 
• Medications. For best results, patients must avoid most antihistamines for at least seven days prior to SPTs. Healthcare providers may also recommend stoppage of other pharmaceutical such as psychiatric medications and beta-blockers prescribed for high blood pressure.⁵ Specific IgE blood tests allow you to remain on these medications prior to testing.
• Skin Disease. For accurate SPT interpretation, you need an adequate area of normal skin. Thus, SPTs may not be an option if you have widespread skin issues such as atopic dermatitis or eczema. Meanwhile, skin condition has no effect on blood testing.⁶
• Age and Skin Reactivity. Skin reactivity can vary with age. So while it has no impact on blood testing effectiveness, SPT reliability isn’t as high in infant and elderly populations.⁶
• Skin Pigmentation. Some sources suggest that it may be more difficult to accurately interpret SPT results in those with increased skin pigmentation.⁷