Image of the Month – Past Images
Manifestations of systemic lupus include a malar or discoid rash, non-erosive inflammatory arthritis, painless oral ulcers, serositis, renal involvement, neurological involvement, and a variety of bloodwork changes. ANA is a sensitive test (a negative ANA essentially rules out lupus) while tests such as dsDNA and anti-Smith are generally considered specific (assuming a good lab technique is used.)
This image shows someone who is cANCA positive when looking under the microscope. The modern naming convention that describes the antibody is pr3-ANCA. pr3-ANCA is a a very specific test for granulomatosis with polyangiitis.
When aspirating a joint effusion, test for the 3 "C's" - culture (with gram stain), cell count, and crystals.