When diagnosing, your doctor will look for very specific signs, symptoms, and disease characteristics. Your doctor will also consider your medical history, physical examination, blood tests, and imaging studies.
Medical History and Clinical Symptoms
Your medical history consolidates information about past medical conditions and your current medical condition. To obtain your medical history, you will likely be asked to fill out a written questionnaire at your first appointment.
Be ready for your medical history by having a list of current medications, medication allergies, past and present medical conditions you are being treated for, and the name of your primary doctor and other specialists, along with their contact information.
Keep a symptom diary. A symptom diary can help you keep track of pertinent facts about your condition and also help you track changes that may occur. With the diary, you are more inclined to give your doctor a good overall picture of the symptoms you are experiencing.
Your doctor will perform a physical examination to try to see any visible signs and symptoms that point to arthritis:
- Redness/warmth around a joint (inflammation)
- Joint stiffness or tenderness
- Joint fluid or swelling
- Bumps or nodules
- Pattern of affected joints (e.g. symmetric or asymmetric)
- Limited range of motion
After a medical history and physical examination have been completed, your doctor will likely need more information. Blood tests can provide more specific information and often serve to confirm what the doctor suspects is the diagnosis. Blood tests are also used to monitor disease activity and treatment effectiveness after a diagnosis has been established. On your initial visit, your doctor will most likely order only a few of these tests, based on your medical history and examination.
- Rheumatoid Factor - Rheumatoid factor is an antibody or immunoglobulin which is present in about 70 to 80 percent of adults who have rheumatoid arthritis.
- Erythrocyte Sedimentation Rate - The erythrocyte sedimentation rate (ESR) is also known as sedimentation rate or sedrate. The test is an indicator of the presence of nonspecific inflammation.
- C-reactive Protein (CRP) - C-reactive protein is a protein which is produced by the liver following tissue injury. Plasma levels of CRP increase quickly following periods of acute inflammation or infection, making this test a better indicator of disease activity than the sedrate which changes more gradually.
- Anti-cyclic Citrullinated Peptide Antibody Test (anti-CCP) - Anti-CCP is a blood test which has become more commonly used and is ordered if rheumatoid arthritis is suspected. Moderate to high levels of anti-CCP in a patient's blood confirm the diagnosis in someone who is felt clinically to have rheumatoid arthritis. The test is more specific than rheumatoid factor.
- Antinuclear Antibodies (ANA) - Antinuclear antibodies (ANA) are abnormal autoantibodies (immunoglobulins against nuclear components of the human cell). The test is based on indirect immunofluorescence. Moderate to high antinuclear antibody levels are suggestive of autoimmune disease. Positive antinuclear antibody tests are seen in more than 95 percent of systemic lupus erythematosus patients, 60 to 80 percent of scleroderma patients, 40 to 70 percent of patients with Sjogren's syndrome, and 30 to 50 percent of rheumatoid arthritis patients, among others.
- Complete Blood Count - The complete blood count determines the WBC (white blood cell count), RBC (red blood cell count), hemoglobin, hematocrit, several red blood cell indices and the platelet count. Elevated white blood cell counts suggest the possibility of an active infection. Patients taking corticosteroids may have an elevated WBC due to the medication. Chronic inflammation can cause a low red blood cell count. Low hemoglobin and hematocrit may be indicative of anemia associated with chronic diseases or possible bleeding caused by medications. The platelet count is often high in rheumatoid arthritis patients, while some potent arthritis medications can cause platelets to be low.
- HLA Tissue Typing - Human Leukocyte Antigens (HLA) are proteins on the surface of cells. Specific HLA proteins are genetic markers for some of the rheumatic diseases. Patients may be tested to see if they have the genetic markers. HLA-B27 has been associated with ankylosing spondylitis and other spondyloarthropathies. Rheumatoid arthritis is associated with HLA-DR4.
- Uric Acid - High levels of uric acid in the blood (known as hyperuricemia) can cause crystals to form which are deposited in the joints and tissues, causing painful gout attacks. Uric acid is the final product of purine metabolism in humans.
For certain types of systemic rheumatic diseases, biopsies of certain organs can provide important diagnostic information. Also, joint fluid analysis can provide a doctor with many details about the health of a person's joint.
Your doctor may order x-rays (radiographs), which are pictures of your bones and joints; they do not show cartilage, muscles, and ligaments. X-rays can reveal deformities and abnormalities.
MRIs, or Magnetic Resonance Imaging scans, produce cross-sectional images of your body by using a magnetic field and radio waves. Precise information about bones, joints and soft tissues is provided. Very small changes in the body can be detected using MRI.
Diagnosis Is Result of Many Factors
A single symptom or a single test result is not enough to diagnose arthritis. Certain symptom patterns and tests are used to rule rule out specific types of arthritis. It can be an arduous process when you want quick answers. The process begins when you say to yourself "I think I have arthritis. Now what?"
Diagnosis of Arthritis. Healthlink Medical College of Wisconsin. 5/21/07.
Guide to Lab Tests. Arthritis Foundation. 5/21/07.