ovemight (fluid deprVation, urine osmolality usually exceeds 600 mOsmo/1 (sp.gr,>1015) in more formal tests,fluid deprivation fOR upto 24 hrs

Normal filtration barrler is impervioua to molecules öf molecular w1 >aboul 60,000 Dall ons. Proteinurla - (a) in glomerular injury. the amount of albumin increases (b) Microalbuminuria helps early detection öf diäbetic nephropalhy (c) Assessing the Selectivity' of filtration. barner by calculating the proportional clearance of a large, molecule, such as IgG (150,000 Dairons) comparad with a small molacule such as albumin (66.500 Daltons) is öf use In children with nepnrotlc syndrome, a setectivity Index <0>1015) in more formal tests,fluid deprivation for upto 24 hrs or injecllon öf antidiuretic hormone (vasopressin tannate) should increasa urlnary osmolality to 750 mOsmol/1 or mare. 2 Urinary acidifcätion - Kdneys most excrete 70-100 mmol of non-volatile acids/day, otheiwise plasma pH falls and urine pH is high pH of urine can be assessed by dipstck A more formal lest is the acid load test Ammonium chloride 100 mg/kg is grven orally over 30-60 minutes (to avoid vomiting) Urine pH and plasma bicarbonate are measured ovar 3 hrs Tha bicarbonate concentrarion should fall below 18mmol/ 1 andurlna pH belcw53 in metabolic acidosis. plasma bicarbonate is already <20mmol/1>