What HLA-B27 is
HLA-B27 is a version of a gene that helps the immune system recognise proteins. You inherit it; it doesn't change over your life, so the test only needs to be done once.
Most people who carry HLA-B27 never develop any disease. In India, a few percent of the general population carry it, and only a small fraction of carriers develop spondyloarthritis.
Why doctors test for it
- Most people with ankylosing spondylitis / axial spondyloarthritis carry HLA-B27
- It is also linked with reactive arthritis, acute anterior uveitis (a painful red eye), and arthritis with psoriasis or inflammatory bowel disease
- In someone with inflammatory back pain, a positive result makes axial spondyloarthritis more likely and is part of the ASAS classification criteria
Positive result — what next?
- Back pain that is worse with rest, better with movement, began before 45 and has lasted 3 months? See a rheumatologist — an MRI of the sacroiliac joints may be needed.
- No symptoms? Nothing to do. You don't need treatment or repeat tests.
- A red, painful eye with blurred vision? See an eye doctor the same day.
Negative result — what does that mean?
A negative HLA-B27 makes ankylosing spondylitis less likely but does not rule it out — a minority of people with the condition are negative. Symptoms and imaging still guide the diagnosis.
Common questions
Does HLA-B27 positive mean I have ankylosing spondylitis?+
No. Most carriers never develop it. It raises the likelihood only when you also have symptoms such as inflammatory back pain.
Can HLA-B27 become negative with treatment?+
No. It is a gene you are born with. Treatment controls the disease, not the gene.
Should my children be tested?+
Usually not, unless they have symptoms. Testing healthy relatives is not recommended because most carriers stay well.
Have a result you're worried about?
Bring the report — results only make sense alongside your symptoms and an examination. Walk-in, no appointment needed.
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