Histocompatibility antigen test

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Blood test

Bone Tissue

A histocompatibility antigen blood test looks at inherited proteins on the surface of cells. The results from such a test can be used to match donated tissue to organ transplant recipients.

HLA typing; Tissue typing

Blood is drawn from a vein, usually from the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic. An elastic band is placed around the upper arm to apply pressure and cause the vein to swell with blood.

A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. During the procedure, the band is removed to restore circulation. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

In infants or young children:

The area is cleansed with antiseptic and punctured with a sharp needle or a lancet. The blood may be collected in a pipette (small glass tube), on a slide, onto a test strip, or into a small container. A bandage may be applied to the puncture site if there is any bleeding.

No preparation is necessary.

When the needle is inserted to draw blood, you may feel moderate pain, or only a prick or stinging sensation. Afterward, there may be some throbbing.

HLA (human leukocyte antigens) are proteins found in the membranes (outer coating) of nearly every cell in the body (all cells that have a nucleus). These antigens are in especially high concentrations on the surface of white blood cells (leukocytes).

HLA antigens are the major determinants used by the body's immune system for recognition and differentiation of self from non-self (foreign substances). There are many different major histocompatibility (HLA) proteins, and each person possesses only a small, relatively unique set that is inherited from their parents. It is unlikely that 2 unrelated people will have the same HLA make-up.

Children, on average, will have one-half of their HLA antigens that match one-half of the mother's antigens. The other one-half of the child's antigens will match one-half of the father's antigens. This is particularly important in identifying good matches for tissue grafts and organ transplants, such as a kidney transplant or bone marrow transplant.