- C-reactive protein (CRP) – to check for inflammation
- Erythrocyte sedimentation rate (ESR) – to check for inflammation
- Complete blood count (CBC) – to check for anemia, a complication of the chronic inflammation associated with AS, and increased numbers of white blood cells as a marker of inflammation
- HLA-B27 – to determine if a person has this gene, which increases the risk of developing AS
- X-rays or other imaging tests
Early diagnosis allows for interventions that may help to prevent or delay complications of the condition.