1. Dr. Abdulrahman Al-Ajlan

2.  The function unit in the kidney is the nephron. Each kidney contains approximately 1 million nephrons  The functions of the kidneys include:  1-Regulation of water, electrolytes and acid base balance.  2- Excretion of the products of protein and nucleic acid metabolis: urea, creatinine, uric acid, sulphate and phosphate.  3- The kidneys are endocrine organs, producing a number of hormones and also it is controlled by others. 2

3.  It is used as a tool for evaluation of renal functions. Urinalysis also serves as a quick indicator of an individuals glucose status and hepatic biliary function.  Physical characteristics  Visual appearance Color, odor, turbidity, pH, Volume 750 to 2000 ml/24 h, average about 1.5 L per person. 3

4.  For a routine UA, a 10-20 ml aliquot from a well mixed sample is enough for accurate analysis.  Polyuria is observed in cases of diabetes mellitus and insipidus.  Anuria and/or oliguria (< 200 ml/day) is found in nephritis, end-stage renal disease, urinary tract obstruction and acute renal failure. 4

5.  The specific gravity of urine is defines as the weigh of the urine divided by the weight of the water standard (1.00).  SG gives an indication of density of a fluid, depending on the concentration of dissolved total solids.  Normal range for urinary SG is 1.005 to 1.030.  Low SG can occur in diabetes insipidus, where it may never exceed the range 1.001 to 1.003.  High SG can be seen in diabetes mellitus, congestive heart failure, dehydration, liver disease. 5

6.  Routine urine chemical analysis is rapid and easy performed by using strips (these strips are plastic coated with different reagent bands direct toward different analytes.  The analytes routinely tested are glucose, protein, ketones, nitrite, and bilirubin/ urobilinogen.  Glucose and ketones  Glucose and ketones are normally absent in urine.  Protein: reagent strips are used as a general qualitative screen for proteinuria. They are specific for albumin. 6

7.  Nitrite  The gram-negative bacteria produce enzyme that reduction of nitrate to nitrite  The reaction  Nitrite + p-arsanilic acid -----diazonium compound --addition N1naphtheylethylene diamine --pink color  A negative result does not mean that no bacteriuria is present. A gram- positive pathogen, such as the staphylo Entero, or streptococci may not produce nitrate reducing enzymes. 7

8.  Bilirubin/ urobilinogen:  In case of hepatic or jaundice, bilirubin levels will rise in serum, this lead to excretion of excess waste via the kidney. Reagent strip tests for bilirubin involve its diazotization to form a brown azo dye.  Proteinuria  May be defined as the excretion of more than 150 mg of protein per 24 h.  In kidney disease, the urine protein content may vary from normal amounts to more than 30 g per day. 8

9.  When more than 5 g of protein are lost in the urine each day, hypoproteinemia and massive edema may result. This is called nephritic syndrome.  As a general rule, the amount of protein in the urine has a direct relationship to the severity of the kidney damage. 9

10.  In the US, kidney disease is the ninth leading cause of death; diabetes and high blood pressure are the most common causes of chronic kidney failure. (If you have diabetes or high blood pressure, you have a greater risk of developing kidney disease. any diseases that affect the blood vessels, including diabetes, high blood pressure, and atherosclerosis (hardening of the arteries), can impair the kidneys’ ability to filter blood and regulate fluids in the body. 10

11.  Kidney disease often causes no symptoms until late in its course and can lead to end-stage kidney failure, which is fatal unless a dialysis machine is used or a kidney transplant is performed.  There are more than 100 disorders, diseases, and conditions that can lead to progressive destruction of the kidneys. 11

12.  The kidneys control the quantity and quality of fluids within the body. They also produce hormones and Vitamins that direct cell activities in many organs; the hormone renin, for example, helps control blood pressure. When the kidneys are not working properly, waste products and fluid can build up to dangerous levels, creating a life- threatening situation. Among the important substances the kidneys help to control are sodium, potassium, chloride, bicarbonate HCO3- (measured indirectly as CO2), pH, calcium, phosphate, and magnesium. 12

13.  Glomerular diseases are those that attack the blood filtering units of the kidneys. Diabetes and high blood pressure can lead to glomerular disease. Diseases of this type cause more cases of chronic kidney failure than any other cause.  For that reason, routine blood and urine tests are especially important; they detect blood or protein in the urine and abnormal chemical levels in the blood, such creatinine and blood urea nitrogen (BUN), early signs of kidney disorder and failure. 13

14.  Blood levels of BUN and creatinine are measured from time to time to see if the kidney disease is getting worse. The amount of calcium and phosphate in the blood and the balance of serum and urine electrolytes can also be measured, as these are often affected by kidney disease.Hb, measured as part of a complete blood count (CBC) may be measured (the kidneys make a hormon, erythropoietin, that controls red blood cell production). 14

15.  Urine total protein can be used to test the effects of treatment in diabetes and nephrotic syndrome. Parathyroid hormone, which controls calcium levels, is often increased in kidney disease and is often checked to see if enough calcium and vitamin D are being taken to prevent bone damage. 15

16.  Creatinine and creatinine clearance  Creatinine is an endogenously produced compound derived from both the phosphorylation of creatine by creatine kinase in brain and muscle cells and by the spontaneous nonenzymatic dehydration of creatine caused by muscle contraction. 16

17.  Synthesis of creatine:  It is synthesized from glycine and arginine plus a methyl group from adenosyl methionine.  Phosphocreatinine function as a store of high energy phosphate in muscle. The amount of phosphocreatine is proportional to muscle mass.  Creatinine is a catabolic end product. Creatinine is not reutilized but excreted from the body via the urine.  Creatinine is a sensitive indicator of malfunction (diagnosis and follow up of kidney disease), because creatinine is normally rapidly removed from the blood and excreted. 17

18. ◦ Creatinine Clearance: ◦ Clearance = the volume of plasma which is completely "cleared" from creatinine, 18