1. Skin Test
2. Challenge Test
3. Blood Test
Skin Test: Which is the most common test, a needle that contains the allergens is used to barley pierce the skin or "scratch". If the patient is allergic, they will react after about 15 minutes.
Challenge Test: This test is usually done for food or medication allergies. A small amount of the suspected allergen is taken by the mouth or inhaled through the nose. Although, it is very important for a doctor to be present.
Blood Test: This test is usually done when the doctor feels it is the best option. This test is usually an option if the patient had a severe or life threatening reaction, if the patient is taking medication that could interact with the allergen, or if the patient has a skin condition that could interfere with the skin test.
Hope this helps!