1.Urine AnalysisDiploma of Biochemical Analysis 2007/2008Urine AnalysisThe kidneys continuously form urine. It is actually an ultrafiltrate of plasma from whichglucose, amino acids, water and other substances essential to body metabolism havebeen reabsorbed. The physiologic process by which approximately 170,000ml of filteredplasma is converted to the average daily urine output of 1200ml is complex. Bloodchemistry, blood pressure, fluid balance and nutrient intake, together with the general stateof health, are key elements in this entire metabolic process.Urine Constituents:Normal urine is actually a highly complex aqueous solution of organic and inorganicsubstances. The majority of the constituents are either waste products of cellularmetabolism or products derived directly from certain foods that are eaten. The totalamount of solids in a 24-hour urine sample averages around 60 g. Of this total, 35 g areorganic and 25 g are inorganic. Organic substances: Urea, a metabolic waste product produced in the liver from the breakdown of protein and amino acids, accounts for almost half of the total dissolved solids in urine. Other organic substances include primarily creatinine and uric acid. Inorganic solids: The major inorganic solid dissolved in urine is chloride, followed by sodium and potassium. Small or trace amounts of many additional inorganic chemicals are also present in urine. Hormones, vitamins and medications. Others: Although they are not a part of the original plasma filtrate, the urine may also contain formed elements such as cells, casts, crystals, mucus and bacteria. Increased amounts of these formed elements are often indicative of disease. Some normal urine constituents excreted (in g/24 hours)Urea25-30 Potassium2-4Uric acid0.6-0.7Calcium0.2-0.3Creatinine 1.0-1.2Magnesium0.1Hippuric acid 0.7 Chloride7Ammonia 0.7 Phosphate1.7-2.5Amino acids 3Sulfate 1.8-2.5Sodium 1-5 (NaCl 15.0)Mohammed Al-Gayyar -1-

2. Urine Analysis Diploma of Biochemical Analysis 2007/2008Urine collection: Clean-catch, midstream urine specimen collected after cleansing the external urethral. A cotton sponge soaked with benzalkonium hydrochloride is useful and non-irritating for this purpose. A midstream urine is one in which the first half of the bladder urine is discarded and the collection vessel is introduced into the urinary stream to catch the last half. The first half of the stream serves to flush contaminating cells and microbes from the outer urethra prior to collection. Catherization of the bladder through the urethra for urine collection is carried out only in special circumstances, i.e., in a comatose or confused patient. This procedure risks introducing infection and traumatizing the urethra and bladder, thus producing iatrogenic infection or hematuria. Suprapubic transabdominal needle aspiration of the bladder. When done under ideal conditions, this provides the purest sampling of bladder urine. This is a good method for infants and small children.Urine specimens: Random collection: it is taken at any time of day with no precautions regarding contamination. Early morning collection: it is collected before ingestion of any fluid. This is usually hypertonic and reflects the ability of the kidney to concentrate urine during dehydration, which occurs overnight. If all fluid ingestion has been avoided since 6 p.m. the previous day, the specific gravity usually exceeds 1022 in healthy individuals.Mohammed Al-Gayyar-2- 3. Urine AnalysisDiploma of Biochemical Analysis 2007/2008 Second-voided specimen: First sample after the first void of the day. It may contain cells that are destroyed during stasis in the bladder while the patient sleeps and therefore not seen in the first morning specimen. Post prandial collection: At a timed interval (for example, two hours) after the patient has eaten. This is the best sample for confirming the presence of elevated urobilinogen. May also be used to detect glucose. Day specimen: Usually collected from 9:00 a.m. to 8:00 p.m. Used for quantitative determinations of analytes that may undergo a diurnal variation or be diet dependent. Night specimen: Usually collected from 8:00 p.m. to 8:00 a.m. Used for quantitative determinations of analytes that may undergo a diurnal variation or be diet independent. Timed: Requires collection at certain time as 2 hour volume and 24 hour volume.Mohammed Al-Gayyar -3- 4. Urine AnalysisDiploma of Biochemical Analysis 2007/2008 Routine urinalysis (UA) and related testsUrinalysis is an essential procedure for patients undergoing hospital admission or physicalexamination. It is a useful indicator of a healthy or diseased state and has remained anintegral part of the patient examination. Two unique characteristics of urine specimens canaccount for this continued popularity:1. Urine is a readily available and easily collected specimen.2. Urine contains information about many of the bodys major metabolic functions and this information can be obtained by simple laboratory tests.General characteristics Chemical determinationsMicroscopic examinationColour: pale yellow to amberGlucose: negativeCasts negative: occasional hyaline castsAppearance: clear to slightly hazyKetones: negativeRed blood cells: negative or rareSpecific gravity: 1.0051.025 with a normal Blood: negativeCrystals: negative (none)fluid intakepH: 4.58.0; average person has a pH of Protein: negativeWhite blood cells: negative or rareabout 5 to 6Volume: 6002,500 ml/24 h; average 1200 Bilirubin: negativeEpithelial cells: few; hyaline casts 01/lpfml/24 h(low-power field)Urobilinogen: 0.54.0 mg/dNitrate for bacteria: negativeUrine strips:They are plastic strips to which chemically specific reagent pads are applied to the coating.The reagent pads react with the sample urine to provide a standardized visible colourreaction within 30 seconds to one minute depending on the specific panel screen. Urineanalysis by strips depends on the following procedure:1. Mix the urine to be tested by inverting the sample several times.2. Completely immerse all reagent areas of the strip briefly but completely in the urine.3. Remove excess urine by drawing the strip across the top of the container or pressing the edge of the strip against an absorbent paper.4. Compare test areas closely with corresponding colour charts on the bottle label at the times specified. Hold strip horizontally and close to the colour blocks.Mohammed Al-Gayyar-4- 5. Urine Analysis Diploma of Biochemical Analysis 2007/2008 General characteristics 1- Urine VolumeUrine volume measurements are part of the assessment for fluid balance and kidneyfunction. The normal volume of urine voided by the average adult in a 24-hour periodranges from 600 to 2500 ml; the typical amount is about 1200 ml. The amount voided overany period is directly related to the individuals fluid intake, the temperature and climate,and the amount of perspiration that occurs. Children void smaller quantities than adults do,but the total volume voided is greater in proportion to their body size.The volume of urine produced at night is