Positive Rheumatoid Factor

When there is prominent joint pain in multiple joints but no swelling, several possibilities come to mind:

• There is arthritis (joint inflammation) but it cannot be seen, at least not yet. Examples include early rheumatoid arthritis or lupus, although there are nearly always other indications by symptoms, physical examination and blood tests. In general, rheumatoid arthritis cannot be diagnosed without joint swelling.

• The joints involved are deep (such as hips and shoulders), so swelling can rarely be seen even with marked inflammation. An example is polymyalgia rheumatica (PMR) which causes sudden onset of pain and morning stiffness in the shoulders and hips among persons ages 55 and older; the RF is usually absent in this condition, though. The condition causes pain but is not a form of arthritis.

• Fibromyalgia, thyroid disease, and high blood calcium (hypercalcemia) are good examples of conditions that can cause terrible bone, joint, and/or muscle pain and yet no arthritis is present. These conditions are not associated with a positive RF so the RF result would be irrelevant to the symptoms--that is, it would be considered a false-positive.

Would you like more information about the rheumatoid factor and various forms of arthritis?

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