DENVER -- For 30-year-old Robyn Nicols, the pain started when she was just 2½ years old. Both of her of her knees have been replaced, her ankles fused and it is getting worse.

"I'm terrified of falling. Tripping and falling 'cause I will just shatter,” Nicols said.

Rheumatoid arthritis, or RA, occurs when the body's own immune cells attack healthy tissues, causing bone to painfully scrape against bone at the joint.

"The onset of RA can be explosive. People can go to bed feeling well one night, and the next morning develop symptoms that can be very dramatic," said Mary Chester Wasko, MD.

Doctors use a variety of tests and X-rays to diagnose it. But now, a new blood test called anti-CCP is giving hope for early treatment.

"It turns out that many people with RA have a positive test years in advance of getting the symptoms," said Marc Levesque, MD, University of Pittsburgh

The blood test is correct 86 percent of the time. But some doctors argue the RA blood markers could be confused with markers for other autoimmune diseases such as lupus, psoriasis or even a viral infection. Still the test could give doctors the head start they need to treat RA before symptoms appear and treat it aggressively with a combination of drugs.

Early warning signs of RA include warmth, swelling and pain in finger joints, wrists and feet. Other symptoms can include fatigue, loss of appetite and fever.