- residual diuresis will be estimated for last 48 hours-between mid and next dialysis Method of investigation All patients and controls ( but hemodialysis) will present after overnight fast. Baseline tests include 24 hr urine collection for: sodium, calcium, phosphorus, creatinine, uric acid, NAG, albumin will be carry out and the same morning fasting sample of blood for: creatinine, cystatin C , uric acid, sodium, glucose, insulin, triglycerides, HDL and LDL cholesterol, calcium, phosphorus, hsCRP. BP will be determined as the mean of three readings taken 5 min apart while sitting. Next in all patients and controls fructose tolerance test will be performed. The test consists of giving 1 gram/kg b.w. of fructose p.o. with blood collection at 0,30,60 and 120 min afterward for serum uric acid determination and uric acid area under the curve will be calculated. The calculated area under curve is the measure of occult uric acid disturbance when compared to controls.