Wisely Ordering

D., FRCPC Division of Rheumatology Mayo Clinic Jacksonville, FL Baptist Health South Florida Boca Raton Regional Hospital Annual Internal Medicine Conference March 22-24, 2024 ©2024 Mayo Foundation for Medical Education and Research | slide-2 Benjamin Wang, M. [...] RDL Laboratories, Inc. [...] • ANA is not reliable – up to 1:160 is borderline; Mayo Lab ELISA: 1.1 - 2.9 Units (Weakly Positive) • dsDNA antibody and C3, C4 probably best, but changes often occur before clinical manifestations are apparent 11 122024 7 ©2024 Mayo Foundation for Medical Education and Research | slide-13 MORE AUTOANTIBODY-DISEASE CORRELATION • Scleroderma • Centromere Ab: 30% of limited scleroderma • Scl70 [...] population • In a patient with typical symptoms, its presence increases the likelihood of true disease to over 95% • Key Clinical Features • Inflammatory back pain • Peripheral oligoarthritis (often large joint) • Inflammatory skin, ocular (uveitis) or bowel disease • Psoriasis ©2024 Mayo Foundation for Medical Education and Research | slide-16 MYOSITIS • Inflammatory, autoimmune myositis such [...] RDL Laboratories, Inc. [...] Los Angeles, CA ©2024 Mayo Foundation for Medical Education and Research | slide-18 VASCULITIS AND ANCA-ASSOCIATED SYNDROMES • c-ANCA and p-ANCA are positive in a limited number of systemic vasculitides • They are associated with certain finer specific antigens • c-ANCA – proteinase 3 (PR3) • P-ANCA – myeloperoxidase (MPO), lactoferrin, and other non-MPO antigens • When c-ANCA and p-ANCA are [...] RDL Laboratories, Inc. [...] Los Angeles, CA ©2024 Mayo Foundation for Medical Education and Research | slide-20 A 68-year-old woman presents with severe dryness of the eyes and mouth. [...] A review of medications does not disclose any strongly implicated drugs that may be causing this. She also complains of joint pain with swelling involving her hands and wrists. Physical examination is remarkable for a mild left foot drop and pinprick sensory deficit along the left L5 dermatome. [...] All of the above may apply – test all of the above antibodies CLINICAL CASE 19 202024 11 ©2024 Mayo Foundation for Medical Education and Research | slide-21 • The immunology lab can be powerful to define diseases but is often a source of confusion • The lab must be applied with knowledge of the clinical scenario, understanding what the clinical likelihood of disease is; the lab tests are used