Laboratory tests include a complete blood count with differential; coagulation studies; serum BUN and creatinine analysis; ANCA testing (c-ANCA and p-ANCA); antigen-specific ELISA [proteinase 3(PR3) and myeloperoxidase (MPO)], analysis of anti-phospholipid antibodies (APL), lupus anticoagulant, anti-cardiolipin (CL) antibodies, anti-β-2 glycoprotein1 (β2GP) antibodies, anti-glomerular basement membrane (GBM) antibodies, anti-nuclear antibodies (ANA), and rheumatoid factor (RF); urinalysis with urine sediment assessment; and a urine drug screen [9,41]. The gene discussed is MPO; the disease is acute promyelocytic leukemia.