Allergy testing is a medical procedure used to identify substances that trigger allergic reactions in individuals. Common allergens include pollen, dust mites, pet dander, and certain foods like peanuts or shellfish. The tests can be performed through skin tests, where small amounts of allergens are applied to the skin, or through blood tests that measure the immune system's response to specific allergens. Once the tests are completed, healthcare providers can determine which allergens are causing problems for the patient. This information helps in creating a personalized treatment plan, which may include avoiding certain allergens, taking medications, or undergoing immunotherapy to reduce sensitivity over time.