The Various Tests Used to Diagnose Rheumatoid Arthritis
Although they are more than 100 conditions that fall under the umbrella term “arthritis,” an autoimmune disease called rheumatoid arthritis is one of the more common. According to the Arthritis Foundation, this condition, causes swelling, pain and stiffness in certain joints which can lead to lasting damage of those joints. Over time, rheumatoid arthritis can be disabling and debilitating.
What Is Rheumatoid Arthritis?
In rheumatoid arthritis, the body’s immune system attacks its own healthy cells inside certain joints, leading to an inflammatory response. This typically shows up as:
- Pain, redness or swelling in one or more joints throughout the body (although symptoms usually are symmetrical, so showing in the same hand, finger or ankle joint on both the right and left side of the body).
- Joint stiffness and pain in the morning that lasts for a while, but loosens up as you move.
- Tingling or numbness in the extremities.
- Decreased range of motion.
- Joint deformity.
Over time, if that inflammation goes unchecked, it does what it’s supposed to do, which is destroy stuff. But it also starts destroying the joint, and in time it can turn into a structural problem because the joint and tendons can get damaged, leading to deformities and loss of range of motion or function.
Rheumatoid arthritis can be very aggressive and may lead to other systemic complications and health problems, including heart disease, diabetes and osteoporosis. That’s why it’s so important to see a doctor if you have symptoms that could be associated with rheumatoid arthritis as soon as possible – early intervention and aggressive management are important to preserving mobility, function and a higher quality of life.
Early diagnosis leads to earlier treatment and obviously better outcomes. The sooner you get to see a doctor and get treated, hopefully you can avoid them developing joint damage.
How Is Rheumatoid Arthritis Diagnosed?
Making a precise diagnosis of rheumatoid arthritis isn’t always easy. Sometimes, the symptoms may be vague or mistaken for those of another condition. “My job is hard because joint swelling and synovitis (swelling and inflammation of the membrane that encases a joint) look the same in all sorts of conditions,” Madhoun says. Therefore, it’s not uncommon for a case of rheumatoid arthritis to look like lupus (a systemic inflammatory disease that affects the joints, skin, blood cells, heart, kidneys, brain and lungs) or another autoimmune condition initially.
But an accurate diagnosis is possible, and your doctor will likely apply a range of tests and exams to sort out what’s causing your symptoms. There are some nuances here and there that can help you distinguish between one and another.
First, your doctor will likely perform an extensive physical exam. This will include careful observation of your affected joints to check for:
- Muscle strength.
Your doctor will also ask for a careful recounting of when and how symptoms began and whether you’ve had any flare ups or improvement of symptoms over that time. All of this information can provide clues as to what condition you may be facing.
The physical exam is really key in helping make an accurate diagnosis. Rheumatoid arthritis tends to target the small joints of the hands, wrists and feet. Therefore, which joints are symptomatic can be a big clue as to which type of arthritis you have. Other symptoms, such as fatigue and fever may also be present with other types of arthritis, but when considered in the wider context of symptoms and family history may be evidence of rheumatoid arthritis instead of something else.
In addition to carefully examining you, your doctor will ask lots of questions about your family’s medical history, because genes certainly do play a role in patients developing rheumatoid arthritis. Dr. Esther Lipstein-Kresch, chief of rheumatology at ProHEALTH Care in New York agrees: “There’s definitely a genetic component. There are some genes that have been identified that give people an increased risk for the development of rheumatoid arthritis. If you have a close relative such as a parent, sibling or child who has rheumatoid arthritis, that may increase your risk of developing the disease, too.
Once the physical exam and the family history have been completed, you’ll likely have blood drawn to look for certain markers that can signify whether inflammation is present. Expert notes that the starting point for RA is an autoimmune or inflammatory problem, many of these tests look for signs of inflammation in the body. Not all of these tests are specific for rheumatoid arthritis, as other autoimmune diseases may also produce similar elevations of inflammatory markers, so bloodwork results should be considered in the context of family history, imaging studies and a thorough physical exam.
Blood tests commonly used to diagnose rheumatoid arthritis include:
- Rheumatoid factor. Most patients who have rheumatoid arthritis have measurable levels of an inflammatory marker called rheumatoid factor in their blood. RF is found in about 85 percent of cases, but some may not have elevated levels of RF and still be diagnosed with rheumatoid arthritis. Expert has been doing this test for decades. However, if you have a negative rheumatoid factor test, it doesn’t completely exclude (a diagnosis of) rheumatoid arthritis. There are people who have zero-negative RA where the rheumatoid factor is negative but (have) same classic findings of the disease. This test will very likely be one of the first tests your rheumatologist runs when an inflammatory form of arthritis like rheumatoid arthritis is suspected.
- Anti-Cyclic Citrullinated Peptide. When your body responds to injury or infection, it produces certain proteins, called antibodies, to help heal the problem. With the inflammation that results from rheumatoid arthritis, an antibody called anti-cyclic citrullinated peptide often increases in the patient’s blood. An anti-CCP test looks for those antibodies to determine whether the body is undergoing an inflammatory response. About 60 to 80 percent of patients with rheumatoid arthritis test positive for these antibodies, and this test may be able to pinpoint a diagnosis early in the disease’s progression. The anti-CCP test can be somewhat predictive for RA. An elevated anti-CCP test could indicate that person could develop RA in the next five or 10 years.
- C-Reactive Protein (CRP). Your doctor may also order a C-reactive protein test, to look for this protein in the blood that indicates chronic inflammation is present, such as occurs with rheumatoid arthritis. This test may also help your doctor understand the extent of the disease based on how high the levels of CRP are in your blood. High levels of CRP may also be associated with infections, cancer, heart disease and even obesity, so this test isn’t specific just to RA, but it can tell your doctor a lot about how much inflammation is present in your body.
- Erythrocyte Sedimentation Rate (ESR). An erythrocyte sedimentation rate test (ESR or sed rate) looks at how quickly erythrocytes (red blood cells) in a sample of blood fall in a thin, vertical tube. ESR is a non-specific test, so high rates of sedimentation simply mean the sample contains more proteins, which are heavier and fall out of solution faster. This result is typically associated with higher levels of inflammation in the blood, which could point to rheumatoid arthritis. It might also indicate you’re dealing with another autoimmune or inflammatory condition, so a high sed rate doesn’t necessarily mean you have rheumatoid arthritis. Conversely, a normal result also does not rule out the possibility of a rheumatoid arthritis diagnosis.
- Antinuclear Antibody (ANA). In autoimmune diseases, such as rheumatoid arthritis, the immune system targets normal cells rather than the foreign invaders they’re designed to fight. Antibodies proliferate as part of this process, and antinuclear antibodies specifically target proteins in the nucleus of a cell. Higher than normal levels of ANA can be a marker of autoimmune disease and these higher levels are often detectable in patients with rheumatoid arthritis.
Many patients also undergo imaging tests so that their doctor can get a closer look at what’s going on inside the joints. The Rheumatoid Arthritis Support Network reports that imaging tests can “help identify signs and progression of RA. These tests essentially look inside the patient’s body so that doctors and other specialists may assess the joint damage as well as detect and interpret specific abnormalities.
These imaging tests may include:
- X-rays. X-rays use radiation to create images of the body. Rheumatologists use X-rays to look at affected joints and determine how much bone erosion has occurred. In rheumatoid arthritis, a soft tissue swelling is looked for, narrowing of the joint space and bone erosion. An X-ray only shows bones, so this type of imaging can be very helpful for seeing what’s happening with the bones, and your doctor may take X-rays regularly to track the rate of bone erosion and joint space shrinkage. While X-rays can tell your doctor a lot about the progression of the disease, it’s not always the best option for detecting RA early because it takes a while for the disease to erode bone.
- Ultrasound imaging. Ultrasound imaging uses high-frequency sound waves to generate pictures of the affected joint. Unlike X-rays, ultrasound technology does not involve radiation but is often better at showing inflammation and early evidence of the disease. Ultrasounds may also be used regularly to monitor the progression of the disease. Given that there are a variety of inflammatory arthritis conditions, pinpointing the right one is helpful for managing it appropriately, and ultrasounds can help do that. Ultrasounds can be very helpful in distinguishing one condition from another.
- Magnetic resonance imaging. While X-rays offer your doctor a look at your bones, MRI machines offer a detailed view of soft tissues in the body. Because of this, MRIs are often better at detecting early signs of rheumatoid arthritis. MRI is helpful in picking up soft tissue swelling and synovitis, a swelling of the synovium – the membrane that encases the joint that becomes inflamed as part of the rheumatoid arthritis disease process. MRI tends to be more sensitive and it can help your doctor pick up the synovitis a little better than X-rays can.
- Computed tomography scanning. CT scans are a type of X-ray that produce cross-sectional images of the body. CT scanning can help your doctor get a better view of joints deeper in the body that may be harder to see on an X-ray.