What is the normal daily urinary protein excretion in a normal adult?

For a healthy young adult, Total filtered protein = GFR concentration of protein in filtrate = 180 L/day 10 mg/L = 1.8 g/day According to the above equation, the amount of protein removed from the lumen will be 1.8 g. In fact, most of the filtered protein is endocytosed and degraded so that the excretion of protein in the urine is normally only 100 mg/day. The endocytic mechanism by which protein is taken up is easily saturated, so a large increase in filtered protein resulting from increased glomerular permeability causes the excretion of large quantities of protein. Ref: Eaton D.C., Pooler J.P. (2013). Chapter 5. Renal Handling of Organic Solutes. In D.C. Eaton, J.P. Pooler (Eds), Vander's Renal Physiology, 8e.