Tests and diagnosis

By Mayo Clinic Staff

The following tests typically help diagnose septic arthritis:

Joint fluid analysis. To discover exactly what bacterium is causing your infection, your doctor usually takes a sample of the fluid within your joint (synovial fluid) through a needle inserted in the space around your joint. Synovial fluid normally appears clear and thick. Bacterial infections can alter the color, consistency, volume and makeup of the synovial fluid. Lab analysis of your synovial fluid iincludes tests to determine what organism is causing your infection. Blood tests. Your doctor may order blood tests to see if bacteria are present in your bloodstream. Imaging tests. X-rays and other imaging tests of the affected joint also may be ordered to assess any damage to the joint.

Jan. 17, 2013