Microalbuminuria is a condition characterized by increased urinary excretion of albumin in the absence of overt nephropathy, and can be used to predict diabetic nephropathy. Diabetic nephropathy is a major cause of death in individuals with insulin-dependent diabetes; and because it is accompanied by irreversible kidney damage and persistent proteinuria, it is a major factor in the decision to initiate hemodialysis.
Early detection of glomerular damage, when it is minimal and reversible, is extremely important. Monitoring urinary microalbumin is an important component of treatment for both Type I and Type II diabetes mellitus.
Methods for monitoring microalbuminuria include measurement of protein excretion in 24 hour, timed, or overnight collections, and determination of the albumin:creatinine ratio in an untimed “spot” urine specimen. Twenty-four hour and timed urine collections may be associated with collection errors including improper timing, missed samples, and incomplete bladder emptying. The concentration of protein in a spot urine sample provides an estimate of the protein excretion rate, but is affected by patient hydration. The ratio of protein or albumin to creatinine in a spot urine sample corrects for variations in hydration and avoids the sources of error associated with 24 hour and timed urine collection.