This article was last reviewed on
This article waslast modified on April 28, 2021.
What Are Allergies? 

Allergies are hypersensitivities that involve reactions of the immune system to substances that do not cause reactions in most people. The substances that trigger the reaction are called allergens.

Allergies affect as many as 40% of people worldwide and have become increasingly common in recent decades. Examples of potential allergens include plants, insect venoms, dander from pets, mold spores, materials, foods, and drugs. They can trigger diverse symptoms that range from mild to severe.  

Several types of tests can be used to determine whether a person is allergic to a specific substance. Because there are diverse kinds of allergens, appropriate testing is important to identify and manage allergies. 

The Role of Allergy Testing

Allergy testing is usually diagnostic, meaning that it is done after someone has had signs of an allergic reaction. By reviewing the symptoms, a primary care physician or allergist can prescribe and perform tests for the most likely allergens. When both past reactions and testing indicate an allergy, it can enable treatment or avoidance of the allergen. 

It’s uncommon to do broad screening for allergies in people who haven’t had any prior allergic reaction symptoms because some tests may have potential false positives that show sensitivity to a substance when no real allergy exists. 

In people who have received treatment for allergies, testing may be used to monitor their response or to determine if they still have hypersensitivity to a substance. 

Getting allergy test results

Allergy test results are usually reviewed with the doctor and in many cases with a specialist known as an allergist. Test results alone often aren’t enough to demonstrate an allergy. Instead, they are typically considered together with past patient reactions. 

Depending on the test results and patient history, more than one test may be used to either confirm or rule out an allergy. 

Types of Allergy Tests

Tests of the blood and skin are the standard ways of identifying potential hypersensitivities. 

Allergen-specific immunoglobulin E (IgE) testing is the most common blood allergy test. IgE is a type of protein known as an antibody that is associated with allergic reactions. Certain types of IgE are related to specific allergens, and elevated levels can reflect a possible hypersensitivity.

The skin prick test is the most frequent allergy skin test. It involves placing a small drop of a potential allergen on your skin and then lightly pricking you with a tiny needle to allow the substance to get just beneath your skin. An intradermal skin test is similar but uses a larger needle to inject the substance deeper into your skin. 

For these tests, doctors usually choose which allergen(s) to test for based on a review of your symptoms. When necessary, they can test for more than one allergen at the same time. 

Often, no further tests are needed to determine if a person has an allergy. However, additional allergy tests, described below, may be used in certain circumstances. 

Other types of blood tests include: 

  • Total IgE testing: This provides a count of all IgE but does not give levels for specific allergens. As a result, it is not regularly used for allergy testing. 
  • Complete blood count (CBC) and white blood cell differential: These tests measure levels of different blood cells, including eosinophils (a type of white blood cell) that may be elevated in people with allergies. 
  • Histamine and tryptase: High levels of these substances in the blood can reflect an active severe allergic reaction, including anaphylaxis, which can be life-threatening. 

Another type of skin testing is called the patch test. It involves applying a possible allergen to the skin, covering the area with a patch, and checking at several intervals over the course of a few days. Patch testing is different from prick and intradermal tests because it does not break the skin. It is most often used when someone has a type of skin condition called dermatitis that develops more slowly than other allergic reactions. 

Blood and skin prick tests can be used to diagnose most food allergies. Other tests for food allergies include: 

  • Oral food challenge: This is a structured test procedure that involves eating gradually increasing amounts of a specific food while being observed for allergic reactions. 
  • Food elimination: Though not a formal test, food elimination means following a specific diet that excludes one or more foods that may be causing allergies. Elimination diets generally last for at least two weeks.  

Looking to get tested?

More than 500+ lab tests available online - confidential, convenient and affordable; no doctor’s referral needed, no insurance required

  • Secure and Confidential Results
  • No Insurance or Referral Needed
  • Affordable Pricing including Doctor's Order
  • 100% Satisfaction Guarantee
1

ORDER YOUR TEST

Online or over the phone, no doctor's referral needed
2

FIND A LAB NEAR YOU

Over 3,500 locations to choose from
3

GET YOUR RESULTS

Most test results sent directly to you in 1-2 days
Powered by HealthTestingCenters.com
1

ORDER YOUR TEST

Online or over the phone, no
doctor's referral needed
2

FIND A LAB NEAR YOU

Over 3,500 locations to choose from
3

GET YOUR RESULTS

Most test results sent directly to you in
1-2 days
You can order your own FDA approved laboratory testing online or by phone and walk-in to a local lab location with a lab requisition to have your testing services performed. Direct-access laboratory testing provides the same FDA approved tests ordered by your physician from the same CLIA certified laboratories. You pay private-pay prices with a credit card, online checkout is easy. There are no additional fees for lab services or blood work. We do not bill your health insurance company.
Powered by HealthTestingCenters.com
1

ORDER YOUR TEST

Online or over the phone,
no doctor's referral
needed
2

FIND A LAB NEAR YOU

Over 3,500 locations
to choose from
3

GET YOUR RESULTS

Most test results sent
directly to you in 1-2 days
Powered by HealthTestingCenters.com
Getting Tested for Allergies

Allergy testing is almost always performed in a controlled medical setting like a doctor’s office or hospital. Allergen exposure can provoke serious reactions that may be unpredictable. As a result, skin tests and oral food challenges require careful protocols to limit severe reactions and to quickly and effectively respond if they occur. 

Blood testing does not involve allergen exposure and does not have the same risk of reaction. In most cases, a blood sample is taken from your arm with a needle in a medical office and then sent to a laboratory for analysis. 

For both skin or blood testing, tests are normally ordered by a doctor based on your past symptoms, allowing the testing to focus on a specific allergen or set of allergens. It is important for anyone with concerns about allergies to talk to their doctor about tests that may be most beneficial in their situation. 

At-home allergy testing

Allergy testing that involves direct exposure is not offered at home and should only be done in a medical office. This is an important safety measure because of the possibility of severe reactions. 

For that reason, at-home allergy tests are almost always blood tests. To take the test, you prick your finger, apply a drop of blood to an included test strip, and then send that sample to a lab. Your blood is analyzed for immunoglobulin proteins associated with different allergies. 

At-home allergy tests do not confirm that you have an allergy and are not a replacement for tests ordered by a doctor. Blood tests are not 100% accurate and may detect elevated immunoglobulin levels when no actual allergy exists. As a result, any results from an at-home test should be reviewed with a doctor who can determine if follow-up testing is appropriate.

Sources and Resources

The following resources provide additional information about the symptoms, causes, and treatment of allergies:

Sources

A.D.A.M. Medical Encyclopedia. Allergies. Updated February 2, 2020. Accessed March 21, 2021. https://medlineplus.gov/ency/article/000812.htm   

Brod BA. Patch testing. In: Fowler JA, ed. UpToDate. Updated July 28, 2020. Accessed March 21, 2021. https://www.uptodate.com/contents/patch-testing

Burks W. Diagnostic evaluation of food allergy. In: Sicherer SH, ed. UpToDate. Updated April 23, 2019. Accessed March 21, 2021. https://www.uptodate.com/contents/diagnostic-evaluation-of-food-allergy 

Burks W. Patient education: Food allergy symptoms and diagnosis (Beyond the Basics). In: Sicherer SH, ed. UpToDate. Updated January 22, 2021. Accessed March 21, 2021. https://www.uptodate.com/contents/food-allergy-symptoms-and-diagnosis-beyond-the-basics 

Commins SH. Food intolerance and food allergy in adults: An overview. In: Sicherer SH, ed. UpToDate. Updated May 28, 2020. Accessed March 21, 2021. https://www.uptodate.com/contents/food-intolerance-and-food-allergy-in-adults-an-overview?

Kowal K, DuBuske L. Overview of skin testing for allergic disease. In: Bochner BS, Wood RA, eds. UpToDate. Updated April 3, 2020. Accessed March 21, 2021. https://www.uptodate.com/contents/overview-of-skin-testing-for-allergic-disease 

Kowal K, DuBuske L. Overview of in vitro allergy tests. In: Bochner BS, ed. UpToDate. Updated February 5, 2021. Accessed March 21, 2021. https://www.uptodate.com/contents/overview-of-in-vitro-allergy-tests

Lavine E. Blood testing for sensitivity, allergy or intolerance to food. CMAJ. 2012;184(6):666-668. doi:10.1503/cmaj.110026 

MedlinePlus: National Library of Medicine. Allergy. Updated May 16, 2018. Accessed March 21, 2021. https://medlineplus.gov/allergy.html 

MedlinePlus: National Library of Medicine. Food Allergy Testing. Updated July 31, 2020. Accessed March 22, 2021. https://medlineplus.gov/lab-tests/food-allergy-testing/

National Academies of Sciences, Engineering, and Medicine. Finding a Path to Safety in Food Allergy: Assessment of the Global Burden, Causes, Prevention, Management, and Public Policy. The National Academies Press; 2017. Accessed March 22, 2001. https://www.nap.edu/catalog/23658/finding-a-path-to-safety-in-food-allergy-assessment-of

Pawankar R, Holgate ST, Canonica W, Lockey RF, Blaiss MS, eds. White Book on Allergy 2013 Update. World Allergy Organization; 2013. Accessed March 21, 2021. https://www.worldallergy.org/UserFiles/file/WhiteBook2-2013-v8.pdf 

Sicherer SH. Oral food challenges for diagnosis and management of food allergies. In: Wood RA, ed. UpToDate. Updated June 17, 2019. https://www.uptodate.com/contents/oral-food-challenges-for-diagnosis-and-management-of-food-allergies

Turnbull JL, Adams HN, Gorard DA. Review article: the diagnosis and management of food allergy and food intolerances. Aliment Pharmacol Ther. 2015;41(1):3-25. doi:10.1111/apt.12984 

UpToDate. Patient education: Allergy skin testing (The Basics). Accessed March 22, 2021. https://www.uptodate.com/contents/allergy-skin-testing-the-basics

UpToDate. Patient education: Food allergy (The Basics). Accessed March 22, 2021. https://www.uptodate.com/contents/food-allergy-the-basics 

Ask a Laboratory Scientist

This form enables patients to ask specific questions about lab tests. Your questions will be answered by a laboratory scientist as part of a voluntary service provided by one of our partners, American Society for Clinical Laboratory Science. Please allow 2-3 business days for an email response from one of the volunteers on the Consumer Information Response Team.

Country
Disclaimer
Thank you for using the Consumer Information Response Service (“the Service”) to inquire about the meaning of your lab test result. The Service is provided free of charge by the American Society for Clinical Laboratory Science.

Please note that information provided through this free Service is not intended to be medical advice and should not be relied on as such. Although the laboratory strives to provide the largest single source of objective, scientific data on patient status, it is only one part of a complex biological picture of health or disease. As professional clinical laboratory scientists, our goal is to assist you in understanding the purpose of laboratory tests and the general meaning of your laboratory results. It is important that you communicate with your physician so that together you can integrate the pertinent information, such as age, ethnicity, health history, signs and symptoms, laboratory and other procedures (radiology, endoscopy, etc.) to determine your health status. The information provided through this Service is not intended to substitute for such consultations with your physician nor specific medical advice to your health condition.

By submitting your question to this Service, you agree to release and hold harmless the American Society for Clinical Laboratory Science and its affiliates or their past or present officers, directors, employees, agents and Service volunteers (collectively referred to as “ASCLS”) and Lab Tests, LLC and its affiliates or their past or present members, managers, officers, directors, employees, agents and Service volunteers (collectively referred to as the “LT Parties”) from any legal claims, rights or causes of action you may have relating to or arising out of your use of the Service or in connection with the responses provided to the questions that you submit to the Service.

ASCLS and the LT Parties hereby disclaim any and all liability arising out of your use of this Service or for any adverse outcome from your use of the information provided by this Service for any reason, including but not limited to any misunderstanding or misinterpretation of the information provided through this Service.