Illness and Conditions - Medical Tests
Tissue Type Test
A tissue type test is a blood test that identifies substances called antigens on the surface of body cells and tissues. Checking the antigens can tell if donor tissue is safe (compatible) for transplant to another person. This test may also be called HLA typing. Antigens can tell the difference between normal body tissue or foreign tissue (for example, tissue from another person's body). Tissue type helps find the best match for tissues or blood cells (such as platelets ). In some cases, a tissue type test may be done to see whether a person has a chance for developing certain diseases that cause the body to attack its own cells, such as autoimmune diseases .
A special pattern of antigens (called tissue type) is present on each person's cells and tissues. Half of each person's antigens come from (inherited) the mother and half from the father. Identical twins have the same pattern, but everyone else has his or her own special pattern. Brothers and sisters have a 1-in-4 chance of having an identical match. Each person's antigen pattern can be "fingerprinted" through a tissue type test.
Two main antigen groups are used for a tissue type test. Class I has three classes of antigens (HLA-A, HLA-B, HLA-C) that are found on some kinds of blood cells. Class II has one class of antigens (HLA-D) that are found only on certain cells in the body. There are many different types of antigens in each category.
Why It Is Done
A tissue type test is done to:
How To Prepare
If you are donating tissue or blood cells, your doctor may want to talk about your medical history—such as a history of cancer, infections, high-risk behaviors, use of drugs, exposure to toxins, and foreign travel. This may be important in understanding whether your donor tissue can be used.
How It Is Done
The health professional drawing blood will:
How It Feels
The blood sample is taken from a vein in your arm. An elastic band is wrapped around your upper arm. It may feel tight. You may feel nothing at all from the needle, or you may feel a quick sting or pinch.
There is very little chance of a problem from having blood sample taken from a vein.
A tissue type test is a blood test that identifies substances called antigens on the surface of body cells and tissues. Checking the antigens can tell if donor tissue is safe (compatible) for transplant to another person.
What Affects the Test
Reasons you may not be able to have the test or why the results may not be helpful include having had a blood transfusion in the past 3 days.
What To Think About
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