Skin Test vs Blood Test for Food Allergies: Which Is More Accurate?

Food allergies and food sensitivities cause annoying symptoms affecting the quality of the sufferer and may lead to severe reactions. Consuming even a very small amount of problematic food can cause mild to serious reactions. The allergy testing helps diagnose food allergies, manage reactions, and prevent life-threatening complications, including allergy blood tests.

The accurate testing allows the sufferers to make the right dietary choices with guidance from a healthcare provider, efficiently manage the reactions, and improve their overall well-being. Early detection, along with a thorough clinical history, can even help prevent fatal reactions and long-term complications, including nutrient deficiencies.

Allergy testing is crucial for knowing the food allergens that can trigger reactions such as fatigue and digestive issues. Mainly, there are two primary methods for food allergy testing: skin tests, intradermal testing, and blood tests. Both types of tests help people recognize food sensitivities and manage them well, contributing to overall well-being.

In this article, you will get insights into skin test vs blood test for food allergies and all you should know about these tests.

A skin allergy test is used to detect substances responsible for causing allergic reactions. The test involves applying a small amount of a possible allergen (foods, dust, pollen) typically on the back or forearm by scratching, pricking, or injecting under the skin surface.

When the immune system responds to a specific allergen, redness, swelling, or a small raised bump appears on the spot, generally within 15-20 minutes. It shows that your body is allergic to that substance. The skin allergy test is minimally invasive and involves a small amount of time, offering immediate results. Usually, the skin allergy test is used to detect food, drug, environmental allergens, and contact dermatitis.

Skin Prick Test: A common method to recognize immediate allergic reactions associated with various substances, such as foods or pollens. A small amount of the possible allergen is applied to the skin on the back or on the forearm. The skin is gently scratched or pricked to allow the allergen to enter the surface below the skin. The appearance of redness or raised bumps within 15-20 minutes indicates an allergic reaction.

Intradermal Test: This type of allergy test is used to diagnose sensitivities when the skin prick test is indecisive. A small amount of allergen is injected into the skin, typically on the forearm. If, within 15-20 minutes, redness and a raised bump appear at the injected site shows that you are allergic to that substance.

It’s a diagnostic test that assesses a specific type of antibody in the blood to detect allergic reactions to food and other substances. A blood allergy test doesn’t involve direct exposure to allergens and requires a blood draw, which makes it safer for people suffering from severe allergies.

Your blood sample is analyzed for IgE (Immunoglobulin E) antibodies, produced by your immune system in response to allergens. Higher IgE levels, combined with a thorough medical history, show allergy or sensitivity to certain substances.

ELISA (Enzyme-Linked Immunosorbent Assay: It involves detecting and measuring the levels of IgE antibodies in response to allergens. ELISA is used to detect food and other environmental allergies.

RAST (RadioAllergoSorbent Test): The blood sample is examined to assess IgE antibodies to precise allergens. RAST is used to confirm suspected allergies, particularly for cases where skin tests are not suitable.

Allergy tests help recognize trigger substances that cause immune reactions; however, skin allergy tests and blood allergy tests work differently, offering different advantages. Let's understand the differences between skin and blood tests and which allergy test is more accurate, blood or skin.

Talking about skin test vs blood test allergy accuracy, skin allergy tests are extremely sensitive for IgE-mediated reactions and can test for various allergens at once, while blood allergy tests are less sensitive but helpful for detecting allergies when the skin tests are not suitable.

Skin tests offer quick results, typically within 15-20 minutes, while blood test results may take a few days.

Skin tests carry a little risk of severe allergic reaction, but may not be ideal for individuals with high-risk allergies and certain skin conditions that could trigger a specific reaction. On the other hand, blood tests are safer for infants, high-risk patients, and people with skin conditions.

Skin allergy tests offer quick screening for various allergies, including food allergies, drug allergies, and pollen allergies. Blood allergy tests are suitable for individuals who can not take skin tests or those who necessitate safe testing for multiple allergens and who may exhibit allergy symptoms.

Here’s the reference table summarizing the differences between skin tests and blood tests.

Let's understand which food allergy test is suitable for which scenario:

• If you are seeking immediate results, usually 15-30 minutes.

• If you have mild to moderate allergies as severe allergies could lead to a life-threatening reaction.

• If you want to test for multiple allergens in one go, such as foods, dust, and pollen, including suspected allergens.

• If you have healthy skin without any rashes or skin conditions that may interfere with the skin test.

• If you have severe allergic reactions or are at risk of developing the same.

• If you have skin condition, damaged, or sensitive skin.

• If you want to get safely tested for various skin allergens without skin exposure.

• If you had a positive skin test, but want to reconfirm alongside.

It's not always about skin test vs blood test for food allergies; sometimes combining both types of tests can offer a better picture. A combination of both tests can offer a comprehensive understanding of allergies and sensitivities, especially after a positive test.

• Detects both immediate reactions as well as delayed sensitivities.

• Reduces the risk of missing certain hidden allergies. Allows the healthcare professionals to plan tailored dietary and lifestyle modifications.

Both tests help diagnose various allergies; however, the accuracy and limitations of skin tests vs blood tests for food allergies depend on the type of allergy and other factors.

Skin test is usually considered extremely sensitive for diagnosing immediate IgE-mediated allergies. It can test for various allergens in one go, offering quick results. There may be a little risk of false positives in case the skin reacts to irritants instead of true allergens.

Blood tests are considered less sensitive for diagnosing immediate allergies. In case you have rashes, skin conditions, or a risk of severe reactions, skin tests can not be performed; blood tests come in handy here. These tests offer quantitative results measuring the IgE levels, allowing the tracking of the severity of allergy.

Generally, skin tests are considered more accurate for immediate allergic reactions, while blood tests are considered more suitable for high-risk individuals who can not get skin testing done.

Skin test vs blood test allergy accuracy can be affected by various factors, as mentioned below:

• Medications: corticosteroids, antihistamines, and certain antidepressant medications can interfere with skin test reactions.
• Skin Conditions: Sunburned skin, damaged skin, dermatitis, and eczema can affect the skin test results.
• Age: Young children and older adults may have weaker reactions during the skin tests.

Skin tests vs blood tests for food allergies are easily available in most cities in India. The cost of these tests may vary depending on the diagnostic center, laboratory, type of test, and the number of allergens tested.

The typical cost of blood allergy tests ranges between INR 700 to INR 12,000. Some diagnostic centers offer specialized panels, and the cost ranges between INR 39,00 to INR 13,300. The cost of skin tests typically ranges between INR 1500 to INR 3000. MyDiagnostics offers skin tests and blood tests for food allergies at reasonable prices, so book your test now.

Understanding the preparation and proper preparation for allergy testing ensures a safe procedure and accurate results.

• Stop taking antihistamines at least one week before the skin tests, as these medications can interfere with the reactions.

• Avoid a skin test if you have sunburn, skin infection, or rash on or around the testing site.

• Wear loose-fitting clothes with short or loose sleeves, allowing easy access to the back or arm.

• Tell your healthcare provider if you have any other allergies and about the medications you are taking.

• Track your symptoms and maintain a record of suspected allergens and symptoms.

Here’s what you should know about your skin prick test and intradermal test results:

• Wheal: Appearance of a raised, round-shaped bump at the testing site is called a wheal, which indicates a local allergic reaction. A larger size of the wheal means a stronger allergic reaction.
• Flare: The redness and swelling around the wheal are caused by histamine release and other chemical production during the allergic response.
• Explanation: Medical professionals usually measure the diameter of the wheal in millimeters. The small wheal indicates mild sensitivity, the moderate wheal indicates the likelihood of allergy, and the large wheal indicates a strong allergic reaction.

Blood tests for allergies assess the Immunoglobulin E (IgE) produced during the immune response to allergens. The results help recognize the type of allergy.

IgE Levels: Higher IgE levels, influenced by environmental factors, show a stronger possibility of allergy to a particular substance.

IgE Measurement: Usually, the IgE levels are measured in kU/L. The results are usually categorized into ranges such as class 0 means no allergy, class 1 means low-level sensitivity, class 2-3 means moderate sensitivity, and class 4-6 means high or extremely high sensitivity.

Considerations: IgE levels are considered with reactions and medical history to confirm the symptoms. Medical professionals use IgE test results to recommend dietary modifications, avoidance strategies, and further testing.

While recognizing food allergies, your healthcare provider recommends a skin prick test or a blood test, and even both types of tests for a comprehensive understanding. Both skin test vs blood test for food allergies differ in terms of procedure, safety, result time, and are suitable for various situations.

When comparing skin tests vs blood tests, skin tests are cost-effective and offer rapid results, making them perfect for quick diagnosis. Blood tests are safest for those with a history or risk of severe allergic reactions and asthma. These are suitable for infants, young kids, older adults, and people suffering from various skin conditions.

Keep a record of possible allergens and associated symptoms, but don’t rely on self-diagnosis, as some food allergies can be life-threatening. Consult your healthcare provider, as recommended in clinical practice, for an accurate diagnosis and the right management and treatment plan.

Worried about the out-of-the-pocket costs? Book your allergy test now at MyDiagnostics and get a gold standard test at a reasonable cost.

***Medical Disclaimer - The following information is for educational purposes only. No information provided on this website, including text, graphics, and images, is intended as a substitute for professional medical advice. Please consult with your doctor about specific medical advice about your condition(s).