Proteinuria from an internists point of view

A basal level of proteinuria is about 30-100 mg/day, the upper limit of basal proteinuria does not exceed 150 mg/day which is considered non-pathology. Albumin accounts approximately 15 % of basal protein in the urine, other plasma proteins (immunoglobulins, β-2 microglobulin, Tamm-Horsfall mucoprotein) comprise the remaining 85 % of total quantity non-pathology proteinuria. Persistent proteinuria present for more than three months already meets the definition of chronic kidney disease independently of the stage of the estimated glomerular filtration rate. Patients are classified as A1-A3 based on the level of albuminuria. Examination of the albumin in the urine is one of the single sensitive indicators of chronic kidney disease. Proteinuria is an independent risk factor for cardiovascular disease, overall mortality and end stage renal failure both in general population and in population with chronic kidney disease. Presence of the urinary protein is associated with a higher mortality rate in critically ill patients. The degree of proteinuria after kidney transplantation predicts graft and patient survival in this population. Pharmacological and non-pharmacological treatments that attenuate proteinuria have been associated with better prognosis of kidney disease.