What do you need to know about an allergy blood test?
Posted By Suborna Fermi
Posted on Sep 12, 2023
Have you ever experienced vomiting, diarrhea, skin rash or shortness of breath after eating certain food? Well, this basically occurs if you have a food allergy. There are many types of allergies. One might experience an allergic reaction because of pollen, pets, and other substances. Most people do not even know if they are allergic to a substance, this is when you need an allergy blood test.
What is allergy?
Allergies appear when your immune system reacts abnormally to certain types of foreign substances that are sometimes harmless.
What is an allergic reaction?
Allergic reaction is your way to respond to an allergen or a specific substance. When you encounter the specific substances for the first time, your body produces immunoglobulin E (IgE). When allergens bind to antibodies IgE, certain cells such as mast cells, basophils and activated eosinophils release chemicals. Chemicals including histamine cause allergic reactions.
What are the risk factors of allergy?
One cannot experience allergic reactions after the first exposure to the specific allergen. Allergies usually develop in childhood, but one may also develop it in their adulthood. People who are under eighteen years, or have a family history of asthma are at risk of having allergies.
What are the common allergens?
As per the studies, one may have allergies to any kind of food. Typically there are eight common food types which can trigger allergic reactions. Foods that can cause allergies are:
- Tree nuts
- Soy products
Apart from the food allergies, some other common allergen are:
- Plant pollen
- Household chemicals
- Certain metals
- Insect stings and bites
- Mold and mildew
- Pet fur
- Cockroaches, moths, and midges
How are allergies diagnosed?
Most people do not know if they have sensitivity to any substances, this is why it is important to contact your doctor if you notice any allergic reactions. Your doctor will run a few diagnostic tests in order to specify the allergen. Healthcare providers mostly prefer allergy blood tests and skin prick tests.
What is the allergy blood test?
An allergy blood test measures the amount of immunoglobulin E (IgE) in your blood sample. Immunoglobulin E is a type of antibodies that our body produces in response to an allergen.
What are the types of allergy blood tests?
There are mainly two types of allergy blood test:
- Total IgE test: This test measures the total IgE amount in the blood.
- Specific IgE test: This test measures the amount of IgE in response to specific allergens.
When do I need this test?
You may require an allergy test for many reasons. Thai test will help to detect:
- Contact dermatitis: Contact dermatitis is a type of rash on the skin that appears when you come in contact with certain substances that you are allergic to. This can occur because of poisonous plants, certain detergents and metals.
- Allergic rhinitis: Hay fever or allergic rhinitis usually occurs because of plant pollen, dust mites, pet danders, mold and others.
- Anaphylaxis: This is the severe stage of an allergic reaction that can be life-threatening and requires immediate medical care.
Your healthcare adviser may prescribe you an allergy test, if you are experiencing an allergic reaction. The common symptoms of allergies include:
- Skin rash
- Swollen face and mouth
- Shortness of breath
- Itchy or red eyes
- Nausea and vomiting
- Runny nose
- Abdominal pain
How do I prepare myself for the test?
You do not need any preparations for the allergy test. However, in some cases, doctors might also prefer fasting for 8 to 12 hours before the test. If you are taking antihistamine, then make sure to talk with your doctor before the test. Your doctor might ask you to stop taking this medicine before the test.
What happens in the allergy blood test?
Only a blood sample is required for this testing. A lab technician will collect a blood sample through a needle from a vein in your arm. Although this is considered as a painless procedure, you might feel a pinching sensation when the needle is inserted. The whole blood collection procedure will take hardly 10 minutes to complete.
What do the test results mean?
Although we all do have a little amount of IgE in our body, an elevated level may indicate an allergy. This allergy test may indicate the presence of an allergy, but it may not indicate the severity of your allergy. Most test reports include the reference ranges, and ask your doctor about your risk of developing anaphylaxis.