Diagnosing arthritis may be difficult. There are more than 100 different types of arthritis. Many symptoms are similar among the different conditions affecting the joints. Arthritis may be generally categorized into the following groups: degenerative arthritis, inflammatory arthritis, metabolic arthritis, and infectious arthritis. Osteoarthritis (also known as degenerative arthritis) is the most common type. Rheumatoid arthritis and gout are 2 other more common types. To make an accurate diagnosis, a healthcare provider may need to:
Review your health history and current symptoms
Examine you, with close attention to your joints
Order lab tests, X-rays, and other imaging tests such as an ultrasound or MRI
Remove fluid from a joint (arthrocentesis)
When reviewing your health history, your healthcare provider may ask the following questions:
Have you had any illnesses or injuries that may explain the pain?
Is there a family history of arthritis or other rheumatic diseases?
What medicines are you currently taking?
Your healthcare provider may also ask:
What symptoms are you having? For example, pain, stiffness, trouble with movement, or swelling.
About your pain:
Where is it?
How long have you had it?
When do you have pain and how long does it last?
Describe your pain (constant, dull, throbbing, stabbing)
How intense is it? (On a scale of 1 to 10, with 1 being no pain, and 10, the worst pain)
What lessens the pain?
What makes it worse?
Is your pain worse certain times of the day?
In addition to a complete health history and physical exam, the following are common lab tests:
Antinuclear antibody. This test measures blood levels of various antibodies, which may be present in people with some types of arthritis.
Arthrocentesis (joint aspiration). This is an exam of joint fluid. A thin needle is put into the joint. Synovial fluid is removed with a syringe and looked at for cell counts, crystal analysis, culture, and other tests.
Complement tests. This test measures the level of complement, a group of proteins in the blood. It is used to help diagnose and monitor systemic lupus erythematosus (SLE) and rheumatoid arthritis.
Complete blood count (CBC). Measures the number of white blood cells, red blood cells, and platelets present in a sample of blood. A low white blood count (leukopenia), low red blood count (anemia), or low platelet count (thrombocytopenia) are linked to some forms of arthritis or the medicines to treat them.
Creatinine. A blood test to monitor for underlying kidney disease.
C-reactive protein (CRP). This protein is high or is elevated when there is inflammation in the body, as in some types of arthritis.
Erythrocyte sedimentation rate (ESR or sed rate). This measures how quickly red blood cells fall to the bottom of a test tube. A high ESR level occurs when there is inflammation in the body. This occurs in some types of arthritis.
Hematocrit (PCV, packed cell volume). Measures the number of red blood cells present in a sample of blood. Low levels of red blood cells (anemia) are common in people with some types of arthritis.
Rheumatoid factor. Checks for an antibody that is present in most people with rheumatoid arthritis.
Urinalysis. Lab exam of urine to check for kidney disease that may be linked to several types of arthritis.
Uric acid. High levels of uric acid are linked to gout.
Imaging methods may give your healthcare provider a clearer picture of what is happening to your joints. Imaging methods may include:
X-ray. X-rays may show joint changes and bone damage found in some types of arthritis. Other imaging tests may also be done.
Ultrasound. Ultrasound uses sound waves (not radiation) to show detailed pictures of soft tissue, tendons, ligaments, and joints.
MRI. MRI images are more detailed than X-rays without using radiation. They may show damage to joints, including muscles, ligaments, and cartilage.
Arthroscopy. This surgical procedure uses a thin tube containing a light and camera (arthroscope) to look inside the joint. The arthroscope is inserted into the joint through a small cut or incision. Images of the inside of the joint are projected onto a screen. It's used to assess any degenerative or arthritic changes in the joint, to detect bone diseases and tumors, to figure out the cause of bone pain and inflammation, and to treat certain conditions.