Renal Function Tests (ii) PDF

Renal Function Tests (ii) Dr Karan Rana Learning Outcomes To develop an understanding of conditions effecting specific regions of the kidney nephron. Have a brief look at acute and chronic kidney failure. Kidney structure 3 Proximal tubular function  Glucosuria....

Renal Function Tests (ii) Dr Karan Rana Learning Outcomes To develop an understanding of conditions effecting specific regions of the kidney nephron. Have a brief look at acute and chronic kidney failure. Kidney structure 3 Proximal tubular function  Glucosuria.  Glucose in urine with a normal blood glucose could indicate malabsorption of glucose in the proximal tubule.  In diabetes mellitus blood glucose is elevated and swamps the reabsorption. 4 Distal tubular function  Assessed by urine concentration tests.  Measure:  Specific gravity (ratio of mass of 1ml of urine : 1 ml H2O).  No good if protein in urine.  Osmolality (related to number of solute particles).  the concentration of a solution expressed as the total number of solute particles per kilogram.  285 mmol/kg in serum.  Normal early morning tests:  Osmolality > 800 mmol/kg; SG > 1.02.  If you deviate from these numbers there can be a problem in the distal tubule. 5 Distal tubular function  Testing:  Inject synthetic analogue of vasopressin intramuscularly and collect samples hourly for the next 3 hours.  Osmolality of urine should increase. 6  Protein and renal function  Albumin (normal < 30mg/24h). 7-10 g protein filtered in 24h TOTAL PROTEIN  Microalbuminuria:  30-300 mg/24h. Most is re-  Detectable with immunoassay stick and analyser. absorbed  Found in diabetic nephropathy.  Macroalbuminuria:  > 300 mg/24h. In urine 150 mg/24 h  Colourimetric dipstick. (50% is uromodulin (Tamm- Horsfall glycoprotein) secreted by tubules, 3.5g/24h in Glomerulo- 30- Type II b2 Tubular obulin g Myeloma urine; nephritis 300mg/24 diabetes damage chains microglobuli plasma (deposition h in urine n in urine albumin