A physician may try to determine whether there is an underlying condition or disease that is causing the joint pain.

After reviewing the patient’s medical history and conducting a physical examination, the physician may ask the patient to describe the pain. Questions that may be asked in a pain assessment include:

• How long has the patient been experiencing pain?
• Is the pain constant, or does it come and go?
• Does resting make the joint pain worse or better?
• Does movement make the joint pain worse or better?

Physicians who suspect joint pain may be caused by an underlying injury, condition or disease may perform several tests. These may include blood tests, such as: 

• Inflammation tests. Erythrocyte sedimentation rate (ESR) and C-reactive protein test indicate whether inflammation is present. This can help a physician better diagnose and treat an underlying condition.
  
  
• Antinuclear antibody test (ANA). This test helps to determine whether a patient has an immune disorder such as systemic lupus erythematosus (SLE), rheumatoid arthritis or scleroderma.
  
  
• Rheumatoid factor test. Part of a blood test that is helpful in  diagnosing rheumatoid arthritis, Sjogren’s syndrome and other inflammatory conditions. Rheumatoid factor is found in the serum of about 80 percent of patients with rheumatoid arthritis.
  
  
• Antibodies to citrullinated peptides. Used to help diagnose rheumatoid arthritis.
  
  
• Serum uric acid concentration. Identifies the presence of uric acid, which helps to diagnose gout.
  
  
• Enzyme test. Above-normal levels of enzymes may indicate trauma or chronic rheumatic diseases such as sarcoidosis.
  

Other tests that may be performed include:

• Urine test (urinalysis). Testing urine samples can help physicians identify and monitor some diseases that cause joint pain, such as gout and lupus.
  
  
• X-ray. This can help a physician identify damage resulting from injury or another cause that could promote joint pain.
  
  
• Range-of-motion (ROM) testing (also called flexibility tests or goniometry). During this test, the patient may move the joint being tested or the physician may move the joint manually. Joint range may be measured with a protractor–like device called a goniometer.
  
  
• Arthrography. A test to help diagnose the cause of joint pain. An iodine solution is injected into the joint area to highlight the joint structures and several x-rays are taken.
  
  
• Joint aspiration and analysis. A test in which fluid is removed from the joint with a syringe and sent to a laboratory for analysis. Irregularities such as bacteria and crystals are noted under microscopic examination. Conditions such as bursitis, arthritis or injuries can cause fluid buildup, which causes swelling and pressure.
  
  
• MRI (magnetic resonance imaging). Test using powerful magnets to produce images on a computer screen and film. Sometimes an MRI is performed to identify joint damage resulting from injury, disease or another cause.

• CAT scan (computed axial tomography). Uses multiple x-ray images combined to provide a three–dimensional image of a body part. CAT scans can show good anatomical detail of bony structures, ligaments and muscles.
  
  
• Bone scans and other radionuclide imaging. Tests using radioactive tracers to highlight internal structures. Nuclear medicine may be used to detect conditions including osteomyelitis, small fractures that do not appear on x-rays, degenerative diseases such as arthritis, cancer and other causes of unexplained joint pain.
  
  
• Ultrasound. A painless, noninvasive test using sound waves to create images of internal structures, including joints. Ultrasound may be used in diagnosing conditions including tendinitis, bursitis, rotator cuff injuries, cancer, sarcoidosis, rheumatoid arthritis and osteoporosis.