Utility of a 24-Hour Urine Collection in Estimating Daily Sodium and Protein Intakes in Living Kidney Donation (P12-058-19)

Abstract

ObjectivesDietary intake can promote good health including blood pressure control from low sodium intake, slow progression of chronic kidney disease (CKD) from low protein diet. Counseling how to control amount of diet may be unpractical unless there is objective information of consumed nutrient. A 24-hour urine collection can provide information regarding the amount of intake nutrient. We present a case of healthy women comes for a living kidney donor evaluation and 24-hour urine collection showed high daily sodium and protein intake and lowering sodium and protein intake are advice for the patient. MethodsA 37-year-old Caucasian woman with a past medical history significant for possible gestational diabetes mellitus comes to pre-living kidney donation clinic. She would like to donate her kidney to her friend who has end-stage renal disease from a lupus nephritis. The patient denies history of kidney diseases, dysuria, gross hematuria, difficulty urination, or history of passing kidney stone. Her weight was 49.4 kg, height was 1.47 m, and body mass index was BMI 22.76 kg/m2. Blood pressure was 126/76 mmHg. Serum creatinine was 0.7 mg/dL and blood urea nitrogen was 14 mg/dL. A 24-hour urine collection showed volume of 1.98 L, microalbumin of 0.24 g, creatinine of 0.9 g, urine urea of 10.1 g, and sodium of 174. ResultsCalculations from the 24-hour urine collection include a daily urinary creatinine excretion of 18.22 mg/kg/day indicating adequately collected urine and creatinine clearance of 89.21 ml/min. Since urine sodium was 174 mmol/day, calculated daily sodium intake was 4 g. Daily protein intake of 16% of daily protein excretion was 11.63 g/day; therefore, daily protein intake was 72.7 g/day or 1.47 g/kg/day. She was advice to decrease amount of daily sodium intake to 62% (2.5 g/day) and protein intake to 68% (1 g/kg/day) of her current daily dietary intake. ConclusionsFrom the 24-hour urine collection, we can estimate 2 important nutrients that our patient took a day. Calculated daily sodium and protein intake were 4 g/day and 1.47 g/kg/day, respectively. These amounts of sodium and protein intake are higher than recommended daily amount for general population. Particularly, for the person who plan to donate their kidney and will have lower than normal renal function after kidney donation, should have more strict diet control. Therefore, calculated amount of daily nutrient intake from a 24-hour urine collection provide practical care and recommendation to person who need dietary guidance with subjective evidence. Funding SourcesNone.