A 65 year old patient presents to the outpatient office complaining of edema in the bilateral lower extremities, flank pain bilaterally and no urine output for two days. Past Medical history includes systemic lupus, diabetes mellitus and arthritis. Outpatient medications include daily aspirin and insulin. What tests are indicated? What signs would indicate support for a diagnosis of renal failure? How is acute renal failure differentiated from chronic renal failure? What are potential causes for kidney dysfunction in this patient?