What is the HLA-B27 test?

The HLA-B27 test is a blood test that detects the presence of the human leukocyte antigen B27 (HLA-B27) protein on white blood cells. HLA proteins play a key role in immune system regulation and how the body distinguishes between self and foreign cells.

HLA-B27 is strongly associated with a group of inflammatory conditions known as seronegative spondyloarthropathies, particularly ankylosing spondylitis. While many people with HLA-B27 never develop disease, its presence significantly increases susceptibility.

This test does not diagnose disease on its own, but provides valuable genetic context when symptoms and imaging suggest inflammatory arthritis.

Why do I need an HLA-B27 test?

The HLA-B27 test is used to support diagnosis when symptoms suggest inflammatory spinal or joint disease, especially when routine blood tests are inconclusive.

You may need an HLA-B27 test if you experience:

• Chronic lower back pain lasting more than 3 months
• Back stiffness worse in the morning or at night
• Pain that improves with movement, not rest
• Inflammation of joints, especially hips or spine
• Recurrent eye inflammation (uveitis)
• Unexplained joint swelling
• Family history of ankylosing spondylitis
• Suspected inflammatory arthritis with negative rheumatoid factor

Conditions commonly associated with HLA-B27 include:

• Ankylosing spondylitis
• Reactive arthritis
• Psoriatic arthritis (axial type)
• Enteropathic arthritis
• Acute anterior uveitis

Benefits of the HLA-B27 test

• Supports early diagnosis of inflammatory arthritis
  Helps identify genetic susceptibility.
• Useful in chronic back pain evaluation
  Differentiates inflammatory from mechanical causes.
• Guides referral to rheumatology
  Supports specialist assessment decisions.
• Clinically established genetic marker
  Widely used in rheumatology practice.
• Aids diagnosis when imaging is unclear
  Complements MRI and X-ray findings.
• One-time lifetime test
  Genetic result does not change.
• Helps assess family risk
  Relevant for first-degree relatives.
• Simple blood test
  No fasting required.

Step by step – how the test works

You can access HLA-B27 testing UK-wide through two options:

1. Clinic appointment
   Attend your nearest UK clinic where a healthcare professional will take your blood sample.
2. At-home or hotel visit (£60 extra)
   A qualified phlebotomist comes to your home or hotel, so you don’t need to travel.

Your sample is analysed in an accredited UK laboratory using immunological or molecular methods.

Your results explained

HLA-B27 negative

HLA-B27 not detected. This reduces the likelihood of certain inflammatory arthritis conditions but does not fully exclude them.

Typical UK interpretation:

• HLA-B27: Negative

HLA-B27 positive

HLA-B27 detected. Indicates increased genetic susceptibility to associated inflammatory conditions.

Typical UK interpretation:

• HLA-B27: Positive

Clinical interpretation required

Many healthy people are HLA-B27 positive and never develop disease. Results must be interpreted with symptoms and imaging.