How Arthritis Is Diagnosed

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. In addition to looking for very specific disease characteristics, your healthcare provider will consider your medical history, physical examination, blood tests, and imaging studies when working to rule other possible causes and ultimately come to a final diagnosis of arthritis.

Though the process may take time in some cases, diligence is important: An accurate diagnosis is necessary to formulating an appropriate treatment plan.

Self-Checks

Most people experiencing joint pain for the first time think they have a minor injury—not 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 healthcare provider.

The warning signs of arthritis include joint pain, stiffness, 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 healthcare provider.

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

By keeping a symptom diary, it will be easier to recall your medical history and track pertinent facts about your condition. With the diary, you can give your healthcare provider a good overall picture of the symptoms you are experiencing.

Even if you have been diagnosed with one form of arthritis, your symptoms may point to a second condition.

Labs and Tests

At your initial consultation, your healthcare provider 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 healthcare provider will likely need more information.

Blood tests can provide this and often serve to confirm what the healthcare provider suspects in the diagnosis. Blood tests are also used to monitor disease activity and treatment effectiveness after a diagnosis has been established.

During your initial visit, your healthcare provider will most likely order a few of the following tests based on your medical history and examination.

Complete Blood Count (CBC)

Among the information that can be determined by performing a complete blood count (CBC) are:

• Red blood cell count (RBC): Chronic inflammation can cause a low red blood cell count.
• White blood cell count (WBC): An elevated white blood cell count suggests the possibility of an active infection. Patients taking corticosteroids may have an elevated WBC due to the medication.
• Hemoglobin and hematocrit: Low hemoglobin and hematocrit may be indicative of anemia associated with chronic diseases or possible bleeding caused by medications.
• Platelet count: The platelet count is often high in rheumatoid arthritis patients, while some potent arthritis medications can cause platelets to be low.

Protein and Antibody Tests

Each of these tests is performed on a blood sample, which may be collected at the same time as the vial(s) taken for your CBC:

• Anti-cyclic citrullinated peptide antibody test (anti-CCP): Anti-CCP is a blood test that is commonly ordered if rheumatoid arthritis is suspected. A moderate to high level of anti-CCP 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). Moderate to high antinuclear antibody levels are suggestive of autoimmune disease. Positive antinuclear antibody tests are seen in more than 95% of systemic lupus erythematosus patients, 60% to 80% of scleroderma patients, 40% to 70% of patients with Sjögren's syndrome, and 30% to 50% of rheumatoid arthritis patients, among others.
• Rheumatoid factor: Rheumatoid factor is an antibody that is present in about 70% to 90% of adults who have rheumatoid arthritis.
• C-reactive protein (CRP): C-reactive protein is produced by the liver following tissue injury or inflammation. 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.
• 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.

Other

• Erythrocyte sedimentation rate: The erythrocyte sedimentation rate (ESR) is a nonspecific indicator of the presence of inflammation. Nonspecific inflammation means that inflammation exists somewhere in the body, but the test does not identify the location or cause.
• 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 healthcare provider with many details about the health of a person's joint.

Imaging

Imaging studies are also used to help formulate a diagnosis. Your healthcare provider may order X-rays, which can reveal deformities and abnormalities of bones and joints. These studies are usually ordered initially to help diagnose osteoarthritis.

While useful in this way, X-rays do not show cartilage, muscles, and ligaments. In addition, what is seen on an image doesn't always correlate with what you're experiencing. For example, you may have a lot of pain, though your X-ray doesn't indicate considerable damage—or vice versa.

Magnetic resonance imaging (MRI) scans produce cross-sectional images of your body by using a magnetic field and radio waves. It can provide precise information about bones, joints, and soft tissues, and detect very small changes in the body.

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 history, physical, examination and blood tests. If there are hand arthritis symptoms, there are distinct patterns of finger joint involvement that 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 tendonitis, bursitis, enthesitis, 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 diseases such as:

• Fibromyalgia
• Lyme disease
• Myelodysplastic syndromes
• Paraneoplastic syndromes
• Polymyalgia rheumatica
• Psoriatic arthritis
• Sarcoidosis
• Sjögren's syndrome
• Systemic lupus erythematosus (lupus)

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 healthcare provider 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.