Tests
Doctors diagnose reactive arthritis based on the person's symptoms, medical history, and on a physical examination. There are a few tests that may be ordered to rule out other causes of the symptoms and to help make a diagnosis. These include:
- Sedimentation rate (ESR) – to check for inflammation; increased with reactive arthritis as well as other diseases
- C-reactive protein (CRP) – to check for inflammation; increased with reactive arthritis as well as other diseases
- Rheumatoid Factor (RF) – to help rule out other diseases such as rheumatoid arthritis
- Antinuclear antibody (ANA) – to help rule out other disease such as systemic lupus erythematosus
- HLA-B27 – to determine if the patient has this gene; being positive can increase the person's risk
Doctors may also order tests to identify the infection that triggered the reaction:
- Synovial Fluid analysis – to look for an infection in the joint
- Chlamydia test – if this is positive, early Treatment can reduce disease progression
- Throat swab and culture
- Genital swab and culture
- Urine culture or urinalysis
- Stool culture
- HIV test
X-rays may be performed to examine the joint for any damage or inflammation.
