Urine Albumin Creatinine Ratio (ACR)

Test includes urine microalbumin, urine creatinine, and microalbumin/creatinine ratio. Diabetes mellitus is the largest single cause of kidney failure. Although the exact pathogenesis of diabetic nephropathy is incompletely defined, it is now recognized that there are detectable abnormalities in kidney structure and function a decade or more before the appearance of any overt evidence of renal disease. The most significant of these abnormalities is a subtle increase in the urinary albumin excretion rate, known as microalbuminuria. Microalbuminuria is not measurable by conventional techniques for detecting proteinuria. It is believed that microalbuminuria represents a reversible stage of renal dysfunction, whereas overt proteinuria reflects irreversible disease. In fact, by the time kidney disease becomes clinically manifest through the appearance of persistent overt proteinuria, the renal lesions are relatively far advanced and renal function progressively and inexorably deteriorates. Proteinuria typically appears about twenty years after the onset of diabetes, whereas microalbuminuria can be detected within the first ten years. Microalbuminuria has been established as a marker predictive of subsequent development of diabetic nephropathy. Periodic monitoring (2-3 times/year) of urine albumin levels in the diabetic patient is therefore recommended so that the initial escalation of renal damage can be detected and appropriate treatment regimens can be instituted.