Tests for Anemia. Anemia is a common complication and blood tests should be taken that determine the amount of red blood cells (hemoglobin and hematocrit) and iron (soluble transferrin receptor and serum ferritin) in the blood.
Possible RA Markers in Synovial Fluid
Analyzing the synovial fluid might prove to be helpful in detecting markers of joint destruction, but this is not commonly performed. Some investigational examples include the following:
- An enzyme called MMP-3 (matrix metalloproteinase 3) is involved with the degradation of cartilage. Its presence in synovial fluid is strongly associated with progressive joint destruction in patients with chronic RA.
- High levels urocortin, a member of the peptide family involved in the stress response, may also be a major player in the RA inflammation.
Imaging Techniques
X-Rays. X-rays generally have not been helpful to detect the presence of early rheumatoid arthritis because they cannot show images of soft tissue. The use of a technique known as dual energy x-ray absorptiometry, however, may be useful in detecting early bone loss in rheumatoid arthritis (2 - 27 months after onset). Evidence of damage on x-rays along with elevated rheumatoid factor is a significant predictor for progressive joint destruction.
Ultrasound. Special ultrasound techniques called power Doppler ultrasonography (PDUS) or quantitative ultrasound (QUS) may be helpful in RA. PDUS may be reliable for monitoring inflammatory activity in the joint. QUS, which is used for osteoporosis, has been used to detect bone loss in fingers, which may prove to be a good indicator of early RA.
Magnetic Resonance Imaging. Specially designed magnetic resonance imaging (MRI) equipment called extremity MRI may be able detect bone erosions in the hands of RA patients where x-rays cannot. Further evaluation is necessary.
Ruling Out Other Disorders
Symptoms of rheumatoid arthritis can be mimicked by things as benign as a bad mattress or as serious as cancer. A number of rare genetic diseases attack the joints. Physical injuries, infections, and poor circulation are among the many problems that can cause aches and pains. It would be impossible to discuss in this report the dozens of other conditions that present themselves with symptoms of joint aches and pains.
Osteoarthritis. Osteoarthritis requires some special mention because it is the most common form of arthritis. It differs from RA in several important respects.
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