Tests and diagnosis

By Mayo Clinic Staff

Your doctor will ask about your symptoms and may perform a physical exam to find or rule out other medical problems. He or she may also recommend one or both of the following tests:

  • Skin test. In this test, your skin is pricked and exposed to small amounts of the proteins found in shellfish. If you're allergic, you'll develop a raised bump (hive) at the test location on your skin. This test is usually completed and interpreted by an allergy specialist.
  • Blood test. Also called allergen-specific IgE antibody test, radioallergosorbent (RAST) test or allergy screen, this test can measure your immune system's response to shellfish proteins by measuring the amount of certain antibodies in your bloodstream, known as immunoglobulin E (IgE) antibodies. A blood sample is sent to a medical laboratory, where it can be tested for evidence of sensitivity to shellfish proteins.

A history of allergic reactions shortly after exposure to shellfish can be a sign of a shellfish allergy, but allergy testing is the only sure way to tell what's causing your symptoms. Adverse reactions to shellfish are also sometimes caused by a nonallergic reaction, such as food poisoning or a bacterial or viral infection.

Jun. 23, 2011