I finally found an article on RA that puts anti-CPP into a context. It was on an electronic medicine website (sorry, but Board rules disallow posting the actual site address). I printed out a few pages & extracted the following info. But not having one iota of medical training, I obviously can't judge accurately what this all means, Leslie; so I hope your drs. can shed more light ASAP. Anyway, here goes...
In the Lab Studies section of this RA article, the following were mentioned:
* ESR and CRP (both correlate with RA disease activity, and CRP correlates with disease progression)
* CBC (findings of interest include anemia, hypochromic anemia, thrombocytosis, leukocytosis, and leukopenia)
* Synovial fluid analysis (findings of interest include evidence of inflammation; and dominance of neutrophils---as opposed to dominance of mononuclear cells; and low glucose levels in pleural, pericardial and synovial fluids)
And now for the main thing I think you're after, immunologic parameters in RA:
* RF is only present in 60% to 80% of RA patients *sometime* in the course of their disease [similar to much we read separately about lupus, this test thus doesn't appear "fully diagnostic" for RA!]
* Antinuclear antibodies are only present in 40% of people with RA, and test results for most of the nuclear antibody "subsets" are negative [yet another parameter that's slippery and not fully diagnostic?!]
* There are some *newer* antibodies, anti-RA33 and anti-CPP ( = anti-citrullinated proteins). At the time this article was written, the tests were sp new that the article states that further validation is needed before they go into general usage... For the anti-CPP test, it's *hoped* that it will have a sensitivity and specificity like the RF test but, better, that it will be able to show positive results earlier in the disease process.
Plus there are imaging studies used in Dx'ing RA:
* Radiographs (hands, wrists, knees, feet, elbows, shoulders, hips, cervical spine & other areas if indicated)
* MRI (usually done on cervical spine if warranted)
* Sonography (joints not easily accessible, like hip joints & shoulder joints in overweight patients)
* Bone scans (to look for inflammation where there is little visible swelling)
* Densitometry (to look for osteoporosis)
There's also an ACR classification system for RA... Similar to the lupus ACR classification system, it's a *classification* system, not a straightforward *diagnostic* system---meaning, I think, that drs. have to use all their training & instincts as well, to make the call. In RA, you need 4 of 7, with (1) items 1 through 4 being present for 6 weeks, and (2) items 2 through 5 must be physician-observed.
Other than all this, PIECE OF CAKE, huh?
Have you tried posting on any of the arthritis boards to see what the latest thinking/usage for this new-ish anti-CPP test is? Have you checked out the foundations for more current info on RA? Has your dr. performed imaging studies to look for signs of joint erosion? Have you asked your dr. if "early" treatment of *your* individual symptoms/findings would be essentially the same, whether it's SLE, RA, or some combination of the two? Asked your dr. to comment himself on how useful, reliable, accurate, etc. the anti-CPP test is viewed as being?
In your shoes, I'd be curious, too, to say the least... Anyway, I hope this helps some, as opposed to muddying the waters more. Please drop us all updates when you can, OK? As always, with my best wishes, Vee