28 Joint Count Test for Arthritis

With the availability of high-tech imaging that can look directly at your bones and tissues and lab tests that measure miniscule amounts of inflammatory chemicals in your blood, it can seem pretty old-school to track inflammatory arthritis, like rheumatoid arthritis, by counting up your swollen and tender joints. But those joint tallies still count, both in research and individual care.

Joint counts involve a health care provider examining your individual joints for signs of swelling and pain. Tallying the number of joints affected and the degree to which they are affected is an important part of monitoring disease activity, helping to determine whether you may be in remission, and assessing whether your current arthritis treatment regimen is working.

Joint count tests are a big part of the Disease Activity Score (DAS), which is a measure of disease activity, and the American College of Rheumatology’s criteria for hitting remission.

Here’s what you need to know about joint count tests when you have arthritis.

What Happens During a Joint Count Exam?

The examiner is looking at each joint to assess whether it is 1) swollen and 2) tender, or painful.

To assess whether a joint is swollen, the examiner will check for excess synovial fluid that has built up in and around a joint. That’s a clear sign, but a joint will also be marked as swollen if the examiner sees or feels fluid moving under pressure from two fingers. If you have longstanding inflammatory arthritis, some of your joints may be permanently enlarged, but that doesn’t necessarily mean swollen. In advanced arthritis, it can be tricky to tell the difference. They also can’t count a joint that has been replaced, even though it was obviously a serious problem in the past.

To check whether a joint is tender, the examiner will use the thumb and forefinger to apply a standard amount of pressure to the joint. “I may say, ‘Does that hurt?’, or ‘Is it painful when I press?’,” says Jennifer Barton, MD, a rheumatologist and associate professor of medicine at Oregon Health & Sciences University in Portland.

For some joints, such as your shoulders, instead of pressing the examiner may count the joint as tender if you feel pain when moving it.

In practice, your rheumatologist will also assess joints for qualities not accounted for in joint counts, such as a joint’s range of motion and how well you can perform a task involving use of the joint.

How Many Joints Are Counted?

There are a few different methods for counting joints; they vary by how many joints are counted and how they are scored.

The number of joints counted goes as high as 68 on some scales, but the standard system used for most patient care and research trials is the 28-joint count. That includes:

  • Shoulders (2)
  • Elbows (2)
  • Wrists (2)
  • Knees (2)
  • Two joints in each finger and thumb (knuckle and second finger joint) (10 per hand or 20 total)

The 28-joint count has been found to track well with scales that involve counting more joints, but it can be misleading if you have higher disease activity in your feet and ankle joints, because it doesn’t include those joints.

Who Does Joint Counts?

Rheumatologists are trained to do joint counts and usually perform them at every visit. In a Canadian study published in 2014, nurses who received brief training and practice on patients achieved excellent agreement in their joint count score with the rheumatologists who trained them. Whoever is involved, it helps to have the same person do your joint counts from visit to visit: While ratings are consistent for an examiner, they can differ slightly from one person to another.

Can I Do Joint Counts Myself?

“We did a systematic review of patient-reported joint counts (compared to a trained assessor) and found that patients were not great at self-assessment of swollen joints but relatively good at reporting tender joint counts,” says Dr. Barton.

Instead of having patients do a joint count, Dr. Barton gets more value from hearing them report their function, their pain, and their global assessment of how they are doing with their arthritis.

How Are Joint Counts Used in an Arthritis Diagnosis?

In diagnosing RA, rheumatologists look for swelling in multiple joints that lasts more than six weeks and doesn’t have another explanation. Although symptoms may start in joints on one side of your body, after a while the joint involvement is usually symmetrical.

Along with the joint count, the doctor will ask about pain, stiffness, and swelling, as well as general symptoms such as fatigue and low-grade fever. Here are more rheumatoid arthritis symptoms to be aware of.

The joint count can also help determine whether your symptoms are a result of fibromyalgia, either on its own or in addition to rheumatoid arthritis. When the tally of a person’s tender joints is at least 7 higher than their number of swollen joints, that’s a good indicator of having fibromyalgia. Read more about fibromyalgia symptoms.

“People with depression or generally high levels of pain may also find more joints tender,” says Barton.

How Are Joint Counts Used to Monitor Arthritis Treatment?

“As a clinician following patients over time, I see a huge value in repeating joint counts, particularly taken in combination with the patient’s and my own global assessment. It is important to look at radiographic changes, but that’s a longer-term way to assess response to therapy than joint counts,” says Dr. Barton.

To monitor your response to treatment, the 28-joint count is included in a Disease Activity Score 28 (DAS-28) that also factors in blood test results looking for inflammation (the erythrocyte sedimentation rate or C-reactive protein) and your rating of how you’re doing (on a 100-point scale). Some disease activity scales include the physician’s global rating, either in addition to or replacing a blood test.

Your doctor will use one of the disease activity scores to determine how you are responding to treatment and whether you are entering remission. “Patient assessments, including joint counts, help us make decisions about whether to escalate or reduce or change therapies, or to perhaps add non-pharmacologic modalities such as hand occupational therapy, physical therapy, or yoga/tai chi,” says Dr. Barton.

Disease activity scores are also key in assessing the effectiveness of new drugs to treat RA. As a baseline, the American College of Rheumatology says that there must be at least a 20 percent or greater improvement in the number of tender and swollen joints for those taking a drug than those on a placebo. More sophisticated criteria that include joints counts and other measures, such as the DAS-28, are also used to assess the benefits of a drug.

Use Our ArthritisPower App to Track Your Disease Activity

Join CreakyJoints’ patient-centered research registry and track symptoms like fatigue and pain. Learn more and sign up here.

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