Description
The HLA-B27 test detects the presence of the HLA-B27 protein, a specific genetic marker found on the surface of white blood cells. This protein is associated with a higher risk for certain autoimmune and inflammatory conditions, particularly those affecting the joints and spine.
Purpose of the Test
- Aid in the diagnosis of autoimmune disorders, especially:
- Ankylosing spondylitis
- Reactive arthritis
- Psoriatic arthritis
- Inflammatory bowel disease–associated arthritis
- Support evaluation of chronic joint pain or uveitis (eye inflammation)
- Determine genetic predisposition in patients with suggestive symptoms
How the Test Works
- A blood sample is collected via venipuncture
- The sample is analyzed for the presence of the HLA-B27 antigen on white blood cells
- Presence of HLA-B27 increases the likelihood of certain autoimmune conditions but does not confirm disease on its own
When to Order
- Chronic back pain or stiffness, especially in young adults
- Symptoms of inflammatory arthritis
- Recurrent eye inflammation (uveitis)
- Family history of HLA-B27–associated diseases
Interpretation of Results
- Positive HLA-B27: Indicates genetic susceptibility; must be correlated with clinical symptoms
- Negative HLA-B27: Makes HLA-B27–related autoimmune conditions less likely but does not completely rule them out
Note: HLA-B27 is a genetic risk factor, not a definitive diagnostic marker. Diagnosis should consider symptoms, imaging, and other laboratory findings.
Fasting not required.
