Updating on the pathogenesis of systemic lupus erythematosus
In RF-positive patients with chronic HCV or other infections associated with polyarticular arthritis, a positive CCP antibody result suggests a likely diagnosis of coexisting RA; HCV patients with cryoglobulinemia, but not RA, typically have negative CCP antibody results.CCP antibody result is highly suggestive of RA (~90%-100%).C-reactive Protein and Erythrocyte Sedimentation Rate C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) measurements are also included in the ACR/EULAR classification criteria for RA (Table 6).Elevated levels are consistent with an RA diagnosis if other laboratory and clinical criteria are met (Table 6).Adding 14-3-3η testing to RF and CCP antibody testing provides greater sensitivity for early RA: 78% with 14-3-3η versus 72% without 14-3-3η.This increased sensitivity may translate into treatment earlier in the course of disease, which can minimize irreversible joint damage.
Although diagnosis of juvenile idiopathic arthritis (JIA) is primarily clinical, ILAR recommends laboratory testing to distinguish between the forms of JIA (Table 3).
However, this test result may be found in some patients with other rheumatic diseases such as SLE, scleroderma, and psoriatic arthritis.
Patients with negative RF and positive CCP antibody results are also likely to have RA.
However, a patient should only be tested if he or she has had at least 1 episode of pain, swelling, or tenderness in peripheral joints.
If the patient has had an episode, the presence of MSU crystals in symptomatic joints indicates gout.