Renal Function Tests
- 1. RENAL FUNCTION TESTS DR. FARHANA ATIA ASSOCIATE PROFESSOR DEPARTMENT OF BIOCHEMISTRY NILPHAMARI MEDICAL COLLEGE, NILPHAMARI
- 2. Renal Function Tests Important in – Detecting presence of disease Assessing progress of disease Not so important in- Determining the cause of disease
- 3. Major Renal Function Tests 1. Urine analysis Physical characteristics- Volume- Color- Pale yellow Odor- Aromatic Appearance (clear/turbid) Specific gravity pH Chemical characteristics Presence of protein Reducing sugar Ketone bodies Blood Bile salts Bile pigments Microscopy- Presence of WBCs RBCs Casts
- 4. Major Renal Function Tests 2. Serum markers of renal function a. Serum creatinine b. Serum urea (or BUN) 3. Estimation of glomerular filtration rate (GFR) a. Creatinine clearance b. Urea clearance c. Inulin clearance 4. Tests of renal tubular function a. Water deprivation test b. Urine acidification test
- 5. Proteinuria Proteinuria can be defined as presence of protein in urine in excess of 150 mg/day. Albumin- 30 mg/day Normal barrier to protein filtration Selective permeability of glomerular capillary Negatively charged basement membrane When negative charges are lost in some disease- protein filtered & appeared in urine.
- 6. Causes of Proteinuria Benign Dehydration Emotional stress Inflammatory process Most acute illness Orthostatic proteinuria Pathophysiological Glomerular Proteinuria Tubular Proteinuria Overflow Proteinuria
- 7. Pathophysysiological Proteinuria Types Daily secretion of Protein Pathophysiologic feature Cause Glomerular >2gm/d ↑ glomerular permeability to protein primary & secondary glomerulopathy Tubular <2gm/d ↓ tubular reabsorption tubular/ interstitial disease Overflow <2gm/d ↑ production of LMW protein Hemoglobinuria Myoglobinuria Multiple myeloma Amyloidosis
- 8. Detection & quantifying urinary protein Qualitative test Dipstick analysis Heat coagulation test Salicylic acid turbidity test (SSA) Quantitative test 24 hrs urinary protein estimation Urine protein to creatinine ratio
- 9. Microalbuminuria Microalbuminuria is defined as the presence of 30- 300 mg of albumin in a 24-h urine collection Early & independent predictor of renal damage in diabetes mellitus
- 10. Microalbuminuria Not detected by routine dipstick test ACR/ albumin creatinine ratio Normal: <3.5 mg A/mmol of creatinine Borderline: 3.5- 10 mg A/mmol of creatinine Definite: >10 mg A/mmol of creatinine AER/ albumin excretion rate Normal: 20-200 μgm/min
- 11. Abnormal constituents of urine Constituent Clinical significance Disease conditions Protein Glomerular proteinuria Nephrotic syndrome Glomerulonephritis Diabetic nephropathy Tubular proteinuria Fanconi’s syndrome Nephrotoxicity due to heavy metal Overflow proteinuria Multiple myeloma Hemoglobinuria Amyloidosis Postrenal proteinuria UTI (Protein derived from UT) Glucose Hyperglycemic glycosuria Uncontrolled diabetes mellitus Renal glycosuria Fanconi’s syndrome
- 12. Constituent Clinical significance Disease conditions Ketone bodies Increased ketogenesis Diabetic ketoacidosis Starvation Blood Hematuria Renal stone UTI Hemoglobinuria Incompatible blood transfusion Malaria Bile salt & bile pigments Obstruction of biliary tree Gall stone Ca head of the pancrease Abnormal constituents of urine