Total Immunoglobulin E (IgE) Test

Overview

An allergy blood sample is used to measure the amount of immunoglobulin E in your blood. In IgE test, your body produces IgE and you may have higher levels of them incase of allergies.

Allergies can be a long-term, common condition that affects your immune system. Your immune system produces antibodies to fight bacteria and viruses that could make you sick. Your immune system considers one or more harmless substances like peanuts or pollen to be a threat when you have allergies. Your immune system produces IgE antibodies to fight the “threat”. This is what causes allergy symptoms.

Allergens are harmful substances that can cause allergic reactions. Common allergens include:

• Pollen
• Dust
• Mold
• Animal dander
• Some food, such as nuts and shellfish
• Some medicines such as penicillin

The type of allergy that you have will be determined by the symptoms. Itching, sneezing, and asthma can all be allergic symptoms.

Why Test Is Done?

To determine if you have allergies, allergy blood tests can be used. There are two types of allergy blood tests.

• Total IgE test, to measure your total IgE antibodies
• A specific IgE test determines how much IgE the body produces in response to one allergen. Each allergen may require a separate test.

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When To Get Tested?

If you experience certain symptoms, your doctor may recommend allergy testing. Symptoms include:

• Nose stuffy or runny
• Sneezing
• Watery, itchy eyes
• Hives (itchy reddened patches on the skin).
• Diarrhea
• Vomiting
• Breathing problems
• Cough
• Wheezing

If you are unable to have an allergy skin test, your provider may order an allergy blood sample. The procedure of skin testing involves applying allergens directly to your skin. If you are allergic to any of the following, skin testing may not be possible.

• Certain skin conditions
• Certain medicines may cause the results to be distorted
• You are likely to experience severe allergic reactions to the allergens used for skin testing

Providers may order allergy blood testing for children as young as three years old in certain instances. This is because they may find the skin test too painful.

How To Get Tested?

An allergy blood test does not require any special preparations.

During the Test

A small needle is used by a health professional to take blood from a vein on your arm. Once the needle has been inserted, some blood will be taken and stored in a vial or test tube. The needle may cause a slight stinging sensation when it is inserted or removed. It usually takes less than five minutes.

After The Test

An allergy blood test is not a risky procedure. Although you may feel a little bit of pain or bruise around the site where the needle was inserted, most symptoms disappear quickly.

Test Results

High IgE results may indicate that you have an allergy. However, the results of a complete IgE test do not reveal what your allergies are or how severe they may be.

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Interpreting Results

An IgE test that shows a high-results indicates that you might be allergic to the particular allergen. However, the IgE level doesn’t necessarily indicate how severe your allergy might be. Your provider might refer you to an allergy specialist if you have any of the above results. The severity of your symptoms and the allergy you have will determine the treatment plan for you.

You should avoid allergens if you are at high risk of anaphylactic shock. An emergency epinephrine medication (an auto-injector of epinephrine) may be necessary. Anaphylactic shock can be caused by allergies to certain foods, medicines, and insect bites.

Ask your provider whether you are at high risk of anaphylactic shock. Also, discuss with your doctor any questions about your results and your treatment plan.

The total IgE results will show how much immunoglobulin you have in your blood. The international units per million of blood (IU/mL), or the nanograms per million of blood (ng/mL) are used to display test results.

Lab results often include a reference range and your test result. Reference ranges are calculated from test results taken from large numbers of people. These ranges provide an indication of the expected IgE levels for healthy individuals.

The results of your test are considered in relation to your overall health and any symptoms you may have. While total IgE levels can help diagnose certain conditions, it is not enough to make a diagnosis. Your doctor should explain the meaning of any test results.

A variety of medical conditions can cause elevated levels of total IgE, including some allergies, asthma, and parasitic infections. To determine the root cause, additional tests may be required.

You can also have very low levels of total IgE due to certain types of immune dysfunction.

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Final Takeaway

Sometimes, allergy blood tests are not accurate. False positives are when the test results say you have an allergy, but you don’t actually have one. If your body reacts to certain substances in foods you have had before the test, this could happen. A false negative is a test that shows you have an allergy but doesn’t prove it.

Your medical history and symptoms may dictate whether your provider orders an allergy skin test along with an allergy blood test. Or, you may opt for a skin test by itself.

FAQs