Although your doctor will probably test your blood for rheumatoid factor – an antibody that can indicate RA – its presence is not a sure sign: While many people with RA test positive for rheumatoid factor, 20 to 30 percent test negative. Sometimes people who don’t have RA test positive. A newer, more specific test measures the presence of anti-cyclic citrullinated peptides (anti-CCP) – proteins found in tissue damaged by RA. People with a positive anti-CCP test are 90 to 95 percent likely to have RA.

Other blood tests look for anemia (a low red blood cell count) or an elevated erythrocyte sedimentation rate (ESR) – how fast your red blood cells cling together, fall and settle at the bottom of a test tube. The higher the rate, the greater the inflammation. Testing for c-reactive protein (CRP) also indicates the extent of inflammation. Doctors frequently take X-rays to assess joint damage – typically bone loss at the edges of a joint, or erosion, combined with a loss of cartilage.

What Causes RA?

Despite extensive research, the cause of RA remains unknown. Scientists have learned much about the immune response and the mechanisms of inflammation over the years, but the events that trigger the abnormal process remain a mystery. Most doctors agree that a combination of genetic and environmental factors is responsible. 

Researchers have identified genetic markers that cause a ten-fold greater probability of developing rheumatoid arthritis. These genes are associated with the immune system, chronic inflammation or the development and progression of RA. Still, not all people with these genes develop RA, and not all people with the disease have these genes. 

Researchers are investigating infectious agents, such as bacteria or viruses, which may trigger the disease in someone with a genetic propensity for it. Other suspects include female hormones (70 percent of people with RA are women) and the body’s response to stressful events such as physical or emotional trauma. Smoking may also play a role.

How Will RA Affect You?

Symptoms vary from person to person, and almost everyone with RA notices a change in symptoms from day to day. Any joint may become involved, but many people first experience inflammation in the knuckles of the hands, feet and wrists. Later, the elbows, shoulders, hips and knees can become involved. Some people experience RA as a mild condition with occasional flares. In other people the disease is continuously active, worsening over time.

RA can make you feel fatigued and sick all over, especially during a flare. You might lose your appetite, lose weight or run a low-grade fever. Your doctor, who will monitor your blood as part of your treatment, may discover you have a low red blood cell count – a condition known as anemia.