Diagnosis of arthritis starts with a medical history and physical examination. Joint X-rays may be normal at first, perhaps showing some swelling. Later the X-rays may show narrowing of the joint space, roughness of the joint surface, or poor alignment of the joint. Bone spurs, which are calcium deposits at the edge of the joint, may also be seen.
Blood tests, including a complete blood count, or CBC, can help detect some types of arthritis. Joint aspiration, which means removing joint fluid with a needle under local anesthesia, can sometimes provide useful information. Rarely, a magnetic resonance imaging, or MRI, is needed to determine the cause or extent of the arthritis.