Blood Tests for Diagnosing Back Pain

Blood tests are generally not used to diagnose the cause of back pain, but they are sometimes used—particularly if your healthcare provider suspects an infection or inflammatory arthritis.

When trying to find the cause of your back pain, your healthcare provider will likely take a medical history, perform a physical exam, and possibly order some diagnostic tests. Such tests generally do not diagnose spine pain.

For example, the National Institute of Arthritis and Musculoskeletal and Skin Diseases (part of the National Institutes for Health or NIH) says that magnetic resonance imaging (MRI) can reveal abnormalities in the spine, but you may not feel pain or experience other symptoms at all.

The National Institute of Arthritis and Musculoskeletal and Skin Diseases also says that healthy, pain-free people can have elevated erythrocyte sedimentation rate (ESR), a blood test historically used as a marker for inflammation.

Common Tests

Below is a list of the most common blood tests used for back pain.

• Complete blood count (CBC) may point to infections or inflammation.
• Erythrocyte sedimentation rate (ESR) is a measure of inflammation that may suggest infection. If your ESR indicates that inflammation is present, the possibility for an underlying cause may be some form of arthritis or, more rarely, a tumor.
• C-reactive protein (CRP) is another blood test that is used to measure inflammation that may indicate an infection or some forms of arthritis.
• HLA-B27 is a genetic marker in the blood that is more common in people with ankylosing spondylitis and reactive arthritis. A test for this marker may be done if your healthcare provider suspects either disease. Ankylosing spondylitis is one type of inflammatory arthritis that usually first affects the sacroiliac joints and hips, and later the spine. Reactive arthritis is a type of arthritis that occurs after an infection in a different body system or area.