I had a blood test for allergies. They came back positive for milk casein then had a skin test that was negative. I'm confused. What do I believe?

Symptoms? Allergists must weigh the results of both skin and blood tests against your own experience with milk casein. This is why the specialty is so challenging. Life is difficult enough without avoiding something that doesn't actually make you sick just on the basis of tests that have many false-positives.

Blood test. I would trust the blood test over the commercially available milk skin test extract. A skin test with real organic milk straight outof the bottle may be helpful.

Both may be true. The antigens used in skin testing may not include milk proteins, but milk is usually included in blood testing for allergy. Skin testing and blood testing for allergy may agree but the immune system can make several different kinds of hypersensitivity reactions. If one test says you are allergic to milk I would tell you to avoid milk, yogurt, ice cream, cream and some cheeses.

Clinical History. Skin testing and / or blood testing for food allergies must be interpreted in light of one's clinical history. If there is no history of reacting to the food in question then there may be very little value in performing any type of allergy test. If there is a history of reacting to a food allergen then the skin and / or blood test can provide valuable data. Follow up with your allergist.