Skin Prick Allergy Test vs. Blood Test: Which is Right for You?

Allergies affect the lives of millions of individuals globally, causing mild irritation to life-threatening symptoms. If you are suffering from an allergy, your doctor may recommend either a Skin Prick Allergy Test or a Blood Test. But how are the two tests different, and what is suitable for you?

In this article, we shall explain how the two tests are conducted, their advantages and disadvantages, and what to consider while choosing the right test for you.

Skin Prick Allergy Test

A Skin Prick Allergy Test (SPT), or scratch test, is a common test for detecting allergies. A small amount of suspected allergen is placed on the skin—usually on the forearm or upper back—and the skin is lightly pricked so the allergen can enter the outer layer. If you’re allergic, a small red bump (similar to an itchy mosquito bite) will appear within 15–20 minutes.

Pros of a Skin Prick Allergy Test

✅ Quick results – Reactions appear within minutes.
✅ Minimally invasive – Only a tiny skin prick is needed.
✅ Highly accurate for environmental and food allergies – Effective in identifying allergens like pollen, pet dander, mold, and certain foods.
✅ Cost-effective – Typically less expensive than a blood test.

Cons of a Skin Prick Allergy Test

❌ Not suitable for people with severe allergies – Those at risk of anaphylaxis may need to avoid this test.
❌ Can cause mild discomfort or itching – Temporary skin irritation is common.
❌ Affected by antihistamines – Medications like antihistamines must be stopped before testing, which may not be ideal for some patients.

Blood Allergy Test

A Blood Allergy Test, or an individual IgE test (e.g., ImmunoCAP or RAST), is a blood test that quantifies the amount of allergy-triggering antibodies (IgE) in your blood. A sample of blood is taken and analyzed in a lab, where it is tested against an array of allergens.

Pros of a Blood Allergy Test

✅ Safer for people with severe allergies – No risk of triggering an allergic reaction.
✅ No need to stop medications – Antihistamines and other drugs won’t interfere with results.
✅ More convenient for some patients – Only requires a single blood draw.
✅ Can test for a wide range of allergens – Useful for food, environmental, and insect venom allergies.

Cons of a Blood Allergy Test

❌ Takes longer to get results – Lab processing can take several days.
❌ More expensive – Blood tests typically cost more than skin prick tests.
❌ May have lower sensitivity – Some blood tests may miss mild allergies.

Skin Prick Allergy Test vs. Blood Test: Which One Should You Choose?

The best test for you depends on several factors:

When to Choose a Skin Prick Allergy Test

• If you want fast results
• If you are not taking antihistamines
• If you don’t have a history of severe allergic reactions

When to Choose a Blood Allergy Test

• If you have a history of anaphylaxis or severe allergies
• If you are taking antihistamines and can’t stop them
• If you prefer a single blood draw over multiple skin pricks

Author Info

Dr Manish Goyal