How Arthritis Is Diagnosed

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Diagnosing arthritis can be confusing and complicated. With over 100 types of arthritis and rheumatic diseases, symptoms—especially early symptoms—can overlap, making it difficult to differentiate between the various types. As part of the diagnostic process, your doctor will look for very specific signs, symptoms, and disease characteristics. Your doctor will consider your medical history, physical examination, blood tests, and imaging studies to rule out some diseases and conditions—and ultimately rule in the final diagnosis. An accurate diagnosis is necessary so that an appropriate treatment plan can be formulated.

Self Checks/At-Home Testing

Most people experiencing joint pain for the first time think they have a minor injury rather than suspecting arthritis. But if you have joint symptoms that last for three days or more, or several episodes of joint symptoms within a month, you should see your doctor.

The warning signs of arthritis include joint painstiffness, swelling, difficulty moving a joint through its normal range of motion, redness, and warmth. Signs and symptoms must not be allowed to persist without consulting a doctor.

Get ready to provide your medical history by organizing in advance the following information: your current medication list, a list of allergies, a list of all medical conditions which are currently being treated, medical conditions you were treated for in the past, and the name of your primary doctor and other specialists along with their contact information.

By keeping a symptom diary, it will be easier to re-create your medical history and to track pertinent facts about your condition. With the diary, you can give your doctor a good overall picture of the symptoms you are experiencing. Once you are diagnosed, an ongoing symptom diary can alert you to changes that should be checked by your doctor.

Even if you have been diagnosed with one form of arthritis, your symptoms may point to a second condition. An accurate diagnosis paves the way to proper treatment.

Labs and Tests

At your initial consultation, your doctor will perform a physical examination to observe any visible signs and symptoms that point to arthritis. After the 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 in 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 a few of these tests, based on your medical history and examination.

  • Rheumatoid Factor: Rheumatoid factor is an antibody which is present in about 70 to 80 percent of adults who have rheumatoid arthritis.
  • Erythrocyte Sedimentation Rate: The erythrocyte sedimentation rate (ESR) is an indicator of the presence of nonspecific inflammation. Nonspecific inflammation means that inflammation exists somewhere in the body, but the test does not identify the cause.
  • C-reactive Protein (CRP): C-reactive protein is a protein that 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 more accurate indicator of disease activity than the sedimentation rate which changes more gradually.
  • Anti-Cyclic Citrullinated Peptide Antibody Test (anti-CCP): Anti-CCP is a blood test which is now commonly ordered if rheumatoid arthritis is suspected. A moderate to high level of anti-CCP in blood essentially confirms the diagnosis in a person who has clinical signs of rheumatoid arthritis. The anti-CCP test is more specific than the test for rheumatoid factor. In clinical practice, both the rheumatoid factor test and anti-CCP test should be ordered together.
  • 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. Testing can determine if certain genetic makers are present. 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. Deposition of uric acid crystals can cause 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.

Imaging

Imaging studies are also used to help formulate a diagnosis. Your doctor may order X-rays (radiographs), which provide images of your bones and joints. X-rays can reveal deformities and abnormalities of bones and joints. They are usually ordered initially to help diagnose osteoarthritis. X-rays do not show cartilage, muscles, and ligaments, however. As well, the amount of joint damage seen on X-ray often doesn't correlate with symptoms. You may have a lot of pain but nothing shows on X-ray, or no pain yet an X-ray shows considerable joint damage.

Magnetic resonance imaging (MRI) scans produce cross-sectional images of your body by using a magnetic field and radio waves. Precise information about bones, joints, and soft tissue is provided by MRI images. Very small changes in the body can be detected using MRI.

MRI uses magnets rather than radiation, and you may not be able to have an MRI if you have some types of metal implants in your body. You will have to lie still for several minutes or more, and some types of machines are enclosed so it can be difficult if you are claustrophobic. The machine can also be rather loud when it's in operation, and you may be given earplugs or headphones or reduce the noise.

Differential Diagnoses

A single symptom or a single test result is not enough to diagnose a specific type of arthritis or rheumatic disease. Certain symptom patterns and tests are combined to rule out certain diseases and rule in a definitive diagnosis. Making it even more complicated is the possibility of having more than one rheumatic disease concurrently.

Osteoarthritis can often be differentiated from inflammatory types of arthritis by the blood tests. If there are hand arthritis symptoms, there are distinct patterns of finger joint involvement can differentiate between OA, RA, and psoriatic arthritis, as well as differences in swelling, stiffness, and the presence of Heberden's nodes.

Iron overload (hemochromatosis) can give similar symptoms as osteoarthritis, especially in the wrist and hand. Specific X-ray findings can help differentiate the two conditions.

If only one joint is affected, the symptoms may be due to soft tissue abnormalities such as tendonitisbursitisenthesitis, muscle strain, or various related syndromes.

If rheumatoid arthritis test results are inconclusive, ambiguous, or negative, further testing may be done to look for autoimmune disorders, connective tissue diseases, and chronic inflammatory diseases such as:

A Word From Verywell

Getting to an arthritis diagnosis can seem like an arduous process when you want quick answers. Your patience is needed as your doctor puts the puzzle pieces together. The diagnosis is really just the starting point of learning to manage your disease. The next steps include understanding your type of arthritis and treatment options.

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Article Sources
  • Arthritis Diagnosis. Health Encyclopedia. University of Rochester Medical Center. Reviewed by Hanrahan and Horowitz.
  • Arthritis Diagnosis. Arthritis Foundation.
  • Kelley's Textbook of Rheumatology. Ninth edition. Elsevier.