Proteinurialbuminuri

Proteinurialbuminuri refers to the presence of abnormal amounts of protein in urine, with particular emphasis on albumin. Proteinuria is the excretion of any urinary protein, while albuminuria specifically denotes albumin in the urine. Albuminuria is the clinically most relevant form because albumin leakage reflects glomerular permeability changes and is associated with kidney and cardiovascular risk.

Assessment and interpretation

Detection typically uses the urine albumin-to-creatinine ratio (ACR) or the protein-to-creatinine ratio (PCR) from a spot urine sample, adjusted for creatinine. Dipstick tests mainly detect larger amounts of protein and are less sensitive for low levels of albumin. Persistent albuminuria is commonly categorized by ACR thresholds: A1 (less than 30 mg/g), A2 (30–300 mg/g, often called microalbuminuria), and A3 (over 300 mg/g). In some settings a 24-hour urine collection remains a reference method. Repeated measurements over time help confirm chronicity and guide management.

Causes

Proteinurialbuminuri can arise from glomerular disorders that increase filtration of albumin (e.g., diabetic nephropathy, hypertensive nephrosclerosis, primary glomerulonephritis) or from tubular or overflow processes that increase tubular protein loss (less common for albuminuria specifically). Acute infections, exercise, fever, or dehydration may transiently elevate protein in urine.

Clinical significance and management

Albuminuria signals higher risk of chronic kidney disease progression and cardiovascular disease. Management focuses on treating the underlying condition and reducing albuminuria, typically with renin–angiotensin system blockade (ACE inhibitors or ARBs). Additional therapies include blood pressure control, glycemic management in diabetes, lipid optimization, and consideration of SGLT2 inhibitors where appropriate. Regular monitoring of albuminuria helps assess response to therapy and CKD risk over time.