Do you have allergies? A cheap and convenient online allergy test can tell you what you may be allergic to. Allergens can be found in everything from the food we eat to the air we breathe, and can cause a wide array of symptoms from itchy eyes to a life-threatening or fatal reaction. Allergy testing can measure the amounts of allergy-related substances such as immunoglobulin E, or IgE, and a complete blood count lab test, or CBC, can help diagnose your allergic reaction to certain substances.