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.

Related Questions

Skin test for food allergies had a +2 reaction to milk and +to soy blood test came back negative still have issues w/milk what do I do?

Food sensitivities. Blood tests are often inaccurate with regards to allergies, intolerances, and sensitivities. The best way to confirm a problem with these foods is to do a 4 week elimination diet. So do not eat dairy or soy products of any kind for 1 month and see how you feels.
FOOD ALLERGIES. The skin test is much more sensitive than the blood test. You should eliminate milk and soy. Also try to stay gluten free. Wholeapproach. Com. And gutbliss diet. Com. Rember allergies develop over time and exposure. So keep a food diary and make sure to rotate food daily. If symptoms persist see an allergist for serum to start immunotherapy.
Milk allergies? The vast majority of adults who can't tolerate milk are actually suffering from lactose intolerance, not an effect of an actual allergy, even if skin testing came back positive. I would recommend either avoiding milk or trying lactose-free milk products. There are even lactase supplements which can allow someone to tolerate milk. If questions, see your doctor or a GI doctor. Good luck.
Avoid it! Allergy tests can be very useful but are not without a margin of error. Listen to your body, if a particular food does not agree with you, avoid it and find other foods that will provide the nutrients you are missing. The tricky thing with eliminating milk is making sure you are getting enough Vitamin D. Calcium and protein are other considerations in planning your diet. Best wishes!