Purpose: The aim of the International Myeloma Working Group was to develop practical recommendations for the diagnosis and management of multiple myeloma–related renal impairment (RI). Methods: Recommendations were based on published data through December 2015, and were developed using the system developed by the Grading of Recommendation, Assessment, Development, and Evaluation Working Group. Recommendations: All patients with myeloma at diagnosis and at disease assessment should have serum creatinine, estimated glomerular filtration rate, and electrolytes measurements as well as free light chain, if available, and urine electrophoresis of a sample from a 24-hour urine collection (grade A). The Chronic Kidney Disease Epidemiology Collabora...