Blood Tests Ordered by Rheumatologists

How important are blood tests in diagnosing arthritis? What blood tests are commonly ordered and what information do they provide about an individual patient?

Laboratory with nurse taking a blood sample from patient
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Also, when a patient has negative blood test results for usual arthritis indicators, but they have clinical symptoms such as pain, redness, warmth, swelling, and stiffness in their joints, do the negative labs preclude a diagnosis of arthritis?

Blood Tests Used

Rheumatologists (doctors who specialize in arthritis and related conditions) typically order blood tests to help confirm or exclude a clinical diagnosis. For example, consider a patient who has a 3-month history of prolonged morning stiffness associated with pain and swelling of the wrists or hand. In this patient, the following blood tests might be ordered to help confirm a diagnosis of rheumatoid arthritis:

The presence of a positive rheumatoid factor or CCP antibody in this patient would help confirm a diagnosis of rheumatoid arthritis. On the other hand, up to 30% of patients with rheumatoid arthritis may not have these antibodies, especially early in their disease. In addition, the presence of rheumatoid factor, especially at a low level, is not uncommon in patients who do not have and never will develop rheumatoid arthritis. The anti-CCP antibody is more likely to be associated with rheumatoid arthritis, so if a patient has a high level, the patient without typical manifestations of rheumatoid arthritis may be more likely to develop the disease.

The other two blood tests mentioned are the sedimentation rate and CRP. These blood tests measure inflammation and are typically elevated in patients with active rheumatoid arthritis. Normal levels do not rule out rheumatoid arthritis, but those patients may be less likely to develop joint damage compared to patients with high levels of inflammation. That's especially true of an elevated CRP.

An antinuclear antibody (ANA) test is important in our example patient to evaluate for systemic lupus erythematosus (SLE). While low levels of ANA are common in rheumatoid arthritis, high levels of ANA in the example patient suggest possible lupus, especially if the anti-CCP and rheumatoid factor are negative.

On subsequent visits, if the rheumatoid factor or anti-CCP are positive, they are usually not re-ordered. The sedimentation rate and CRP, however, are frequently ordered as they can help confirm (in addition to the patient's history and exam) whether the arthritis is active or in remission.


An Overview of Rheumatoid Arthritis

4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Arthritis Foundation. Rheumatoid arthritis.

  2. Venables PJW. Diagnosis and differential diagnosis of rheumatoid arthritis. UpToDate.

  3. American Association for Clinical Chemistry. Rheumatoid arthritis.

  4. Orr CK, Najm A, Young F, et al. The utility and limitations of CRP, ESR and DAS28-CRP in appraising disease activity in rheumatoid arthritis. Front Med (Lausanne). 2018;5:185. doi:10.3389/fmed.2018.00185

By Carol Eustice
Carol Eustice is a writer covering arthritis and chronic illness, who herself has been diagnosed with both rheumatoid arthritis and osteoarthritis.