If a patient's serum creatinine level is elevated and chronic renal insufficiency is suspected, it is important to determine whether the problem is acute or chronic, to determine the cause, to identify secondary causes (including multiple myeloma, renal vascular disease, diabetes mellitus, reflux nephropathy, stone disease with infection, and hypertension), to institute measures to slow the progression of the disease; and to control hypertension, hyperphosphatemia, and acidosis.