Arthritis Home > Tools Used to Confirm Juvenile Rheumatoid Arthritis
Tools for Making a DiagnosisTo help diagnose juvenile rheumatoid arthritis and to rule out other conditions, healthcare providers use a variety of tools. These include:
- Medical history
- Physical examination
- Laboratory tests
The medical history is the child's (or parent's) description of symptoms and when and how they began. Good communication between the child or parent and doctor is especially important here. For example, the description of pain, stiffness, and joint function and how these change over time is critical to the healthcare provider's initial assessment of the disease and how it evolves over time.
An important consideration in diagnosing this condition is the length of time that symptoms have been present. Joint swelling or pain must last for at least six weeks for the healthcare provider to consider a juvenile rheumatoid arthritis diagnosis. Because this factor is so important, it may be useful to keep a record of the symptoms, when they first appeared, and when they are worse or better.
The physical exam includes the healthcare provider's examination of the child's joints, skin, reflexes, and muscle strength.
There is no one single test that a healthcare provider can use to diagnose juvenile rheumatoid arthritis, so he or she will use a combination of tests. One common test is for rheumatoid factor (RF), an antibody (which is a special protein made by the immune system that normally helps fight foreign substances in the body) that is eventually present in the blood of most people with juvenile rheumatoid arthritis.
The RF test helps the doctor tell the difference among the three types of juvenile rheumatoid arthritis. However, not all people with juvenile rheumatoid arthritis test positive for juvenile rheumatoid factor. This is especially true early in the disease. Also, some people test positive for rheumatoid factor, yet never develop the disease.
Other common laboratory tests that may help doctors diagnose the condition include:
- A white blood cell count
- A blood test for anemia
- A test of the erythrocyte sedimentation rate (often called the sed rate or ESR)
- A test for ANA.
ANA is found in the blood more often than RF, and both are found in only a small portion of juvenile rheumatoid arthritis patients.
ESR is a test that measures how quickly red blood cells fall to the bottom of a test tube. Some people with rheumatic disease have an elevated ESR or "sed rate" (cells fall quickly to the bottom of the test tube), showing that there is inflammation in the body. Not all children with active joint inflammation have an elevated ESR.