HLA-B27 antigen

Injury	Disease	Nutrition	Poison

Symptoms	Surgery	Test	Special Topic

Blood test

Overview

Risks

Results

HLA-B27 antigen

Definition:

HLA-B27 is a blood test to detect the presence of HLA-B27 on lymphocytes (white blood cells). See also histocompatibility antigens test.

text continues below

In the past, this test was performed using serum that specifically reacts with HLA-B27 on the cells (known as serologic tissue typing). Newer methods are now available that use genetic testing to identify the type of HLA-B27 in a particular individual. The HLA-B27 gene is designated as HLA-B*2701, HLA-B*2702, or others.

Alternative Names:
Human leukocyte antigen B27
How the test is performed:

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.

How to prepare for the test:

No special preparation is usually necessary.

For infants and children:

The preparation you can provide for this test depends on your child's age and previous experiences. For specific information regarding how you can prepare your child, see the following topics:

Infant test or procedure preparation (birth to 1 year)
Toddler test or procedure preparation (1 to 3 years)
Preschooler test or procedure preparation (3 to 6 years)
Schoolage test or procedure preparation (6 to 12 years)
Adolescent test or procedure preparation (12 to 18 years)

How the test will feel:

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.

Why the test is performed:

The human leukocyte antigens (HLAs) are proteins present on the surface of all body cells that contain a nucleus, and are in especially high concentrations in white blood cells (leukocytes).

HLA antigens are the major histocompatibility antigens for tissue recognition. They are especially important in considering any type of tissue transplant, for example, kidney transplant or bone marrow transplant.