Yes. Yes, blood can be sent to test for allergies, however the "gold standard" is allergy skin testing. This identifies the important allergens in your area, and also demonstrates that the patient reacts to those allergens. If the skin is so irritated, or you cannot stop taking antihistamines or cannot cooperate with skin testing, blood tests are used as an alternative method.
Yes. The old school name is rast but nowadays it is known as immunocap testing. Skin prick testing is more accurate, though.
What is the context. Depends on what you are looking for. No simple test. There are specific tests for certain things (penicillin). There are a few tests done to determine if an individual can tolerate a certain med (G6PD). Mostly, though, it comes down to trial of a med and knowledge of what to look for. For example if you get a cough with ACE inhib (lisinopril) your DR will change you to ARB (valsartan)
Don't worry. It would be very illegal and unethical to test you for street drugs without your consent, unless you were seriously sick and we had reason to think that knowing what drugs were in you would save your life.
No. The most accurate test is your clinical history. What actually happens to you when you get into this-and-that? Especially, don't assume you're safe to eat / inhale / keep as a pet something that seems to make you sick because of some bloodwork.
Absolutely not. You cannot be tested for drugs except in a life-and-death emergency without your consent.
How do I know if I have recently been taking drugs, and I need to get a blood test for allergies, will they test for drugs anyway as a precaution?
Not usually. You should discuss your concerns with the doctor who prescribed the medications. It is not a routine practice to test for allergies or do blood levels for most drugs.
More info/mgt. Milk allergy and lactose intolerance are two different conditions. For milk allergy testing a specific IgE blood test may be ordered If you have GI upset with milk based products including milk chocolate, try avoiding these foods, using a milk substitute such as almond milk and taking lactaid. At your age, lactose intolerance is more likely.
I want to go get a blood test for allergies. Will this assess for all types of allergens? Will it tell if I'm allergic to food dyes?
Uncertain. Every single test needs be interpreted with the history and physical findings in context. Food dye allergy. Other than to red carmine dye, is very rare if non-existent although it was in vogue over 40 years ago.
I asked my dr about getting blood test for allergies & she said instead she'll refer me for regular skin test at allergist. Is that really better?
Yes. A skin test is usually more sensitive than a blood test for allergies. In addition, an allergist has the training to identify which allergies to test for and how to interpret the results of either skin or blood testing.
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?
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.
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.