Allergy Blood Test

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An allergy blood test, also known as a specific IgE test, is a medical test that helps identify what substances (allergens) might be causing your allergic reactions. By measuring specific antibodies in your blood, this test can pinpoint which allergens you’re sensitive to, such as pollen, pet dander, or certain foods.

Why Should You Get an Allergy Blood Test?

To Diagnose Allergies: If you experience unexplained allergic reactions, this test can help identify the culprits.

To Guide Treatment: Knowing your specific allergies helps in creating an effective treatment plan.

To Monitor Allergies: It helps track how your allergies change over time.

Types of Allergy Blood Tests

Total IgE Test: Measures the overall level of IgE antibodies in your blood, which can indicate an allergic condition.

Specific IgE Test: Identifies IgE antibodies to specific allergens. 

Common methods include:

RAST (Radioallergosorbent Test): An older method.

ELISA (Enzyme-Linked Immunosorbent Assay): A newer and more common method.

How is the Test Done?

Collecting the Blood Sample: A healthcare provider draws a blood sample, usually from your arm.

Laboratory Analysis: The sample is sent to a lab where it’s tested for specific IgE antibodies against different allergens.

Understanding the Results

Negative Result: Low or no specific IgE antibodies, suggesting you’re not allergic to the tested substances.

Positive Result: High levels of specific IgE antibodies, indicating an allergy to the tested substances.

Preparing for the Test

Review Medications: Inform your doctor about any medications you’re taking, as some can affect the test results.

No Fasting Needed: You don’t need to fast before an Allergy Blood Test.

Benefits of Blood Tests Over Skin Tests

Safe for Everyone: Suitable for infants, young children, and people with skin conditions.

No Allergen Exposure: Unlike skin tests, you won’t be exposed to allergens during a blood test.

Medication Impact: Antihistamines and other medications don’t affect the results.

Possible Drawbacks

Expense: Blood tests often come with a higher price tag compared to skin tests.

Sensitivity: Sometimes less sensitive than skin prick tests, which might lead to false negatives.

Frequently Asked Questions(FAQ)

Q.1: How long does it take to get results from an allergy blood test?

ANS: Results usually take a few days to a week, depending on the lab.

Q.2: Can I take antihistamines before the test?

A: Yes, antihistamines do not affect blood test results.

Q.3: Are allergy blood tests accurate?

ANS: They are generally accurate, but sometimes less sensitive than skin tests, which may result in false negatives.

Q.4: Is there any risk involved with taking an allergy blood test?

ANS: The risks are minimal, mainly slight bruising or discomfort at the blood draw site.

Q.5: How do I know if I need an allergy blood test?

ANS: If you have unexplained allergic reactions, consult your doctor, who might recommend an allergy blood test.


Getting an allergy blood test is a straightforward step to understanding and managing your allergies. If you have persistent or unexplained allergic reactions, discussing this test with your doctor can provide valuable insights and help you develop an effective allergy management plan. With accurate diagnosis and proper treatment, you can significantly improve your quality of life.