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- Diff Dx:
    - SLE
    - Psoriatic Arthritis
    - Ankylosing Spondylitis
    - Mixed Connenctive Tissue Diseases
    - Reiter's Syndrome
    - Polymyalgia
    - Sjogren's syndrome
    - Crystal deposition disease
    - Septic Arthritis
    - Tuberculous Arthritis ("monoarticular arthritis");

- Discussion:
    - lab tests alone cannot confirm the diagnosis of RA;
    - RF can be present (usually low titers) in normal individuals and in association with other disease states;
    - common lab findings in RA include decreased Hgb, elevated acute phase reactants (Sed Rate and C reative protein), elevated serum cryoglobins, and precipitating antibioties to soluble antigens