This is an excerpt on diagnosis on my upcoming book, My Rheumatoid Arthritis Handbook
Rheumatoid Arthritis is diagnosed using a combination of your
- Doctor’s exam
- Your explanation of your symptoms
- Your history
- Laboratory tests
There is no single blood test that will diagnose RA.
Today there are the ACR-EULAR Classification Criteria for Rheumatoid Arthritis, a clear list of classic symptoms, and blood tests that, although do not confirm RA, are helpful.
The American College of Rheumatology provides guidelines for treatment in the American College of Rheumatology Guideline for the Treatment of Rheumatoid Arthritis.
Reaching a diagnosis of RA requires your explanation of what is going on.
Keeping a log and a good journal will help you inform your doctor of how RA is affecting you. It will help her make the clear assessments that will be added to her physical exam, lab tests and x-rays.
Before you are assessed by the rheumatologist, your family doctor or primary will usually determine that you need to see a specialist. Early symptoms of RA are not always clear cut. Primary doctors may have limited knowledge on the complexity of diagnosing RA. They are also reluctant to start a patient on a DMARD such as methotrexate.
It is up to you to clearly explain your symptoms to give your doctor the clearest picture so she will be able to guide you to the best treatment. Prompt treatment will help you maintain the best function over the long term.
Rheumatologists commonly use this test to help determine a rheumatoid arthritis diagnosis for new patients. This test is used on patients with at least one inflamed joint that has no other explanation for its cause.
Choose one value for each category (A-D); Add the scores. A score of ≥ 6/10 is needed to classify a patient as having RA.
|One large joint||0|
|2-10 large joints||1|
|1-3 small joints, with or without involvement of large joints||2|
|4-10 small joints, with or without involvement of large joints||3|
|>10 joints, at least one small joint||5|
|B.||Serology, at least one test result needed for classification|
|Negative RF and negative ACPA (Blood Test)||0|
|Low positive RF or low positive ACPA (Blood Test)||2|
|High positive or high positive ACPA (Blood Test)||3|
|C.||Acute-phase reactants, at least one test result needed for classification|
|Normal CRP and normal ESR (Blood Test)||0|
|Abnormal CRP or ESR (blood test)||1|
|D.||Duration of Symptoms|
Test yourself. My score was 7. I am seronegative RA.
The 28-joint disease activity score (DAS28) is used to measure the severity of RA. It is an index that combines.
- the number of tender joints
- the number of swollen joints
- ESR or CRP lab test result
- the general health measure score (0-100)
There are a number of web sites that have the formula for the score. It is easy to plug in your criteria to produce a score. A DAS score higher than 5.1 is considered severe RA. Scores between 3.2 and 5.1 are moderate and scores between 2.6 and 3.2 are low. Scores lower than 2.6 indicate remission. An improvement greater than 1.2 is considered a good response. This test evaluates the joints in the hand, wrists, elbows, shoulders, and knees.
A notable problem with the score is that it does not include the feet. Since feet are commonly affected in 90% of those with RA, not including the joints of the feet in the score restricts its assessment value.
My rheumatologist adjusts the score to include involvement of the feet, but I am sure many other doctors do not.
It is a self- administered questionnaire widely used to determine disability among RA patients. It assesses the patient’s ability to perform activities of daily living, pain level and general well-being.
ACR score is usually used in clinical trials to standardize results. In the RA drug package inserts, there is a section that reviews clinical trials. These inserts include ACR determinations.
The ACR score reflects percentage improvement in a patient’s RA. For example, a score of ACR20 states that a patient has improved 20%, a score of ACR50 states that a patient has improved 50%, and a score of ACR70 states that a patient has improved 70%.