A patient with type 1 diabetes is screened for nephropathy. Which urinalysis finding is suggestive of early diabetic nephropathy?

In patients with type 1 diabetes, microalbuminuria is an important early sign of diabetic nephropathy. Microalbuminuria refers to the presence of a small amount of albumin in the urine, typically defined as 30 to 300 mg of albumin per day. This finding indicates that the kidneys are starting to become damaged due to diabetes, as they begin to leak small amounts of protein—specifically albumin—into the urine. Early detection of microalbuminuria allows for timely interventions to slow the progression of nephropathy, such as strict glycemic control and the use of ACE inhibitors.

Other urinalysis findings like red cell casts, white cell casts, and renal epithelial cells typically point to different pathologies. Red cell casts may indicate glomerular bleeding or inflammation, white cell casts suggest infection or interstitial nephritis, and renal epithelial cells may indicate tubular injury. Thus, microalbuminuria is uniquely associated with the early stages of diabetic nephropathy in patients with type 1 diabetes.