Human leukocyte antigen (HLA) testing

Human leukocyte antigen (HLA) testing is also called HLA typing or tissue typing. It is a blood test that identifies antigens on the surface of cells and tissues. It is used to match a transplant recipient (person receiving a transplant) with a compatible donor (person who gives their cells for a transplant).

A pattern of antigens, called a tissue type, is inherited from your parents. Half comes from your mother and half comes from your father. Everyone has their own pattern except for identical twins, who have the same pattern and are an identical match for tissue and blood cells. Brothers and sisters who have the same parents have a 1 in 4 chance of being an identical match.

The transplanted stem cells must match the recipient’s as closely as possible. The greater the number of antigens that match, the more likely a transplant will succeed. Most matches are between close family members (related donors), so the search for a donor starts with a brother or sister.

HLA testing is done to identify your pattern of antigens and to find antibodies to the HLA antigens. The more antibodies found, the higher the likelihood that a transplant will fail.

A sample of blood is taken by inserting a needle into a vein in your arm. Sometimes a swab of cells is taken from inside of your cheek (called a buccal swab) for testing. No special preparation is needed for either method.

The results from HLA testing will let the doctors know whether there is a good match for a stem cell transplant.