Urine osmolarity is very variable, and depends on the pathology of the patient. Urine osmolarity allows the etiological search for a hydroelectrolyte disorder.
Formula: Osm = (Natremia + Serum K) x 2 + Blood Sugar + Uremia.
Urinary creatinine excretion in an adult is approximately 1 g/d, or 8.84 mmol. This value is rounded to 10 for the estimate of 24 h proteinuria. Example: proteinuria/creatinineuria = 700 mg/mmol. Proteinuria for 24 hours is estimated at 700 x 10 = 7 g/d or 7 g/g of creatinine.