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"Rheumatoid Arthritis: A Difficult Diagnosis"
"Learn some of the common methods used to diagnose rheumatoid arthritis.
By HealthTalk Staff
Medically reviewed by Ed Zimney, MD
Rheumatoid arthritis can be very difficult to diagnose in its early stages, as there is no single test to detect it. Symptoms vary from person to person and can mimic those of other joint conditions. As a result, health care providers use several methods and tools to diagnose rheumatoid arthritis.
Medical history: The doctor will ask a patient to describe his or her symptoms, as well as when and how they began. How symptoms such as pain, stiffness, and swelling change over time is especially important to making an accurate diagnosis. In general, a diagnosis of rheumatoid arthritis cannot be made unless the symptoms have been present for at least six weeks.
Physical examination: The doctor will examine joints, muscle strength, skin, and reflexes.
Rheumatoid Arthritis Diagnosis: Laboratory Tests Several laboratory tests are used to diagnose RA:
Rheumatoid factor: If, after reviewing the medical history and performing the examination, the doctor suspects a person has rheumatoid arthritis, he or she may order a blood test to look for the presence of rheumatoid factor, or RF. Rheumatoid factor is a protein made by the immune system. It eventually appears in the blood of about 80 percent of rheumatoid arthritis patients. When it is positive, the amount of RF present in the blood may help the doctor predict the potential severity of and complications from the rheumatoid arthritis.
However, a positive test does not mean a patient has RA, and, likewise, a negative test does not mean a patient does not have RA. The significance of RF results needs to be evaluated on an individual basis and discussed with a patient's personal physician. Test results are reported as numerical values. Since positive and negative ranges vary by age, sex, and the kind of test used, it's best to discuss results with a doctor. Levels of rheumatoid factor can vary with the severity of symptoms and inflammation. RF may not be present at all when the disease is in its earliest stages. So, if an RF test is negative and the patient continues to show signs and symptoms of rheumatoid arthritis, the doctor may suggest repeating the test.
ESR and CRP: Once rheumatoid arthritis is diagnosed, doctors may also order blood tests such as erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP). ESR and CRP tests detect inflammation in the body and help monitor the progress of the disease and responses to therapies.
CBC: In some cases, doctors may order a CBC (complete blood count). This test will check for anemia, since it is not unusual for RA patients to develop this condition. Additionally, it will check the white blood cell count, which may be abnormal in RA patients.
X-rays: Doctors use X-rays and other imaging techniques such as MRI, to see the amount of damage to joints. Usually, the early joint damage in RA is not visible on X-rays, so they will appear normal. Therefore, X-rays often are not helpful in initial diagnosis. However, these early X-rays can be used later to follow the progression of the disease and response to therapies.
Last Updated: 02/12/2008
This section created and produced exclusively by the editorial staff of HealthTalk. © 2009 EverydayHealth.com; all rights reserved. "
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