Chemical-Examination-of-Urine：尿液化学检验课件

Chemical Examination of Urine：尿液化学检验尿液化学检验1、战鼓一响，法律无声。英国2、任何法律的根本；不，不成文法本身就是讲道理法律，也-即明示道理。爱科克3、法律是最保险的头盔。爱科克4、一个国家如果纲纪不正，其国风一定颓败。塞内加5、法律不能使人人平等，但是在法律面前人人是平等的。波洛克Historical PerspectiveMicroscopic examination of urineNot until invention of the microscopeThen clinical usefulness realized6Reagent Strip TestingTechnology and necessityChemical reactions miniaturizedRequired less urineTest results within minutesEasy to performIncreased test utilizationBrunzel,2nd Ed,page 1247Reagent Strip TestingIdeal qualitative screening toolSensitive:Low concentration of substances Negative result=normalSpecific:Reacts with only one substance False negative and false positiveCost effective:Relatively inexpensive tool that provides information about the health statusof the patient8Reagent Strip TestingChemically impregnated absorbent pads attached to an inert plastic stripEach pad is a specific chemical reaction thattakes place upon contact with urineChemical reaction causes the color of the pad tochange Color compared to a color chart for interpretation9Reagent Strip TestingQualitative or semi-quantitative resultsConcentration units(mg/dl)Negative,small,moderate largeNegative,1+,2+,3+,4+Timing of chemical reactions is CRITICALShortest time requirement on one end of strip:30 secLongest time requirement on the other:2 min10Reagent Strip TestingPrinciple of chemical reactionsFalse negative reactionsFalse positive reactionsColor interferencesAlternative testing:used to confirm results that you may think are invalid due toInterfering substanceColor interference(called color masking)11Care and Storage(pg 4)Confirmatory Testing(pg 6)Reading assignment:Textbook,chapter 7Page 124-13012Confirmatory TestingAlternative testing establishes the correctness or accuracy of another procedureOften used when urine is highly pigmentedBilirubin reagent strip ictotest13Confirmatory TestingCharacteristics:Differ in sensitivityIctotest vs Bilirubin reagent stripDiffer in specificitySSA vs Protein reagent stripClinitest vs Glucose reagent stripDiffer in methodology/reactionIdeallywant all 314Differ in SpecificityClinitest reacts with all reducingsubstancesGlucose reagent strip reacts with only one reducing substance:glucose1510 reagent strip testsSpecific gravitypHProteinGlucoseKetonesBloodBilirubinUrobilinogenNitriteLeukocyte EsterasePurpose of the testWhat is normalWhat is abnormalReactionCauses of invalid results16Specific Gravity:PurposeEvaluates the concentrating and dilutingability of the kidneyDensity is related to the amount of substances(solutes)in solutionIncreased density increased solute in solution hypertonic urine concentrated urine Decreased density decreased solute in solution hypotonic urine dilute urine17Specific Gravity:Normal Normal:1.002 1.035Majority of urines:1.010 1.025Physiologically impossible:1.0001.040Dependent upon hydration status18Specific Gravity:TermsIsosthenuriaFixed at 1.010Renal tubules lost absorption and secreting capabilityHypersthenuriaIncreased specific gravityConcentrated urineHyposthenuriaDecreased specific gravityDilute urineSensitivity issues:Pregnancy testingUrinary tract infection19Specific Gravity:MethodsMethods of measurementReagent strip test:indicates ionic solutesRefractometer:indicates amount of total solutesTwo functions of the kidneyMaintain water balance Maintain electrolyte homeostasisPerformed by renal tubules through concentrating and diluting;reabsorbing and secreting water and electrolytes(ionic)20Specific Gravity:Reaction Based on a change in the pKa of a polyelectrolyte on the reagent padIncreased ions in solution causes the polyelectrolyte on the pad to produce free H+Free H+cause a change in pH on the reagent padChange in pH:bromthymol blue indicator21Specific Gravity:Reaction22Specific GravitySensitivity:1.000Specificity:detects only ionic substancesRadiographic dyeMannitolGlucoseDoes not interfere23pH:PurposeKidneys regulate bodys acid-base balance by selective handling of H+and HCO3-Urine pH reflects acid-base status of bodyTreatment protocol may require urine pH be maintained at a specific pH(Aids in identification of crystals(microscope)24pH:NormalNormal:ranges from 4.5 8.0First morning void:acidicPhysiologically impossible:8.01.Urine not handled properly2.Old urine3.Treatment induced25pH:InterpretationMade in conjunction with Acid-base statusRenal function Presence of infection in urinary tractDiet:high protein,low proteinMedicationsAge of urine sample26pH:AbnormalAcidRespiratory acidosisHigh protein dietStarvationUTIAlkalineRespiratory alkalosisVegetarian dietRenal tubular acidosisUTI27pH:ReactionDouble indicator systemMethyl redBromthymol blueAmount of free H+influences acidity of urine and cause pH indicator to change colorNeeded to measure the wide pH range:acid to alkaline28pH:Invalid test results due to:Improper handling of urine sampleContamination of urine vessel prior to collectionRun-over phenomenon 29Protein:PurposeNormal kidneys secrete LITTLE protein15 mg/dl (or 8.0)False negative:Dilute urine Presence of other proteins(Tamm-Horsfall,globulins,myoglobin,free light chains,hemoglobin)35Protein:SSA(Extons Test)Sulfosalicylic Acid(SSA)Precipitation TestAcid will precipitate proteins out of solution causing the solution to become cloudyAmount of cloudiness is related to the amount of protein present36Protein:SSA(Extons Test)Amount of cloudiness is evaluated,thus must use centrifuged urineSensitivity:5-10 mg/dlSpecificity:detects all protein37Protein:SSA(Extons Test)False positive results:Radiographic dyesTurbid urineUncentrifuged urineFalse negative results:Highly alkaline urineDilute urine38Protein:Foam test Shake aliquot of urine and observe color of resulting foamWhite foam:protein present39Protein:Micro-albumin testMeasures very low concentration of albumin(better sensitivity than reagent strip test for albumin)Management of diabetic patientMethods vary:reagent strip test,immunochemical reaction40Glucose:PurposeHealthy normal urine does not contain glucoseNormally,glucose is filtered by the glomerulus and is reabsorbed back into the bloodstream through active transport mechanismGlucose in urine is pathologic41Glucose:PurposeGlucosuriaGlycosuriaCaused by renal and non-renal diseasePre-renal glycosuria:plasma glucose level exceeds renal threshold(diabetes mellitus)Renal glycosuria:plasma glucose level below renal threshold,but tubules cannot reabsorb glucose back into bloodstreamTerms used interchangeably 42Reducing Substances:PurposeReducing Substances:GlucoseOther sugars:galactosemia(inherited metabolic disorder)43Glucose,Reducing SubstancesNormal:negativeAbnormal:Diabetes mellitus:glucoseImpaired renal tubular reabsorption:glucoseInborn error of metabolism:galactosemia44MethodsReagent strip:detects only glucoseCopper Reduction:detects reducing substances45Glucose:Reagent StripDetects only glucoseDouble sequential enzyme reaction46Glucose:Reagent StripSensitivity:30 mg/dlSpecificity:Reacts only with glucoseFalse positive:Strong oxidizing agents(bleach)PeroxidesFalse negative:Ascorbic acid(reducing agent)Improperly stored urine:glycolysis47Clinitest ReactionCopper Reduction Test:Reducing substances are able to reduce copper sulfate to cuprous oxidePass-through phenomenonAll children 2 years:metabolic disorder(galactosemia)48Clinitest ReactionSensitivity:250 mg/dlSpecificity:Reacts with all reducing substancesReducing sugars:glucose,galactose,fructose,lactose,maltose(NOT SUCROSE)False positive:any reducing substance(Ascorbic acid)False negative:radiographic dye 49Ketones:PurposeKetones are intermediary products of fat metabolism50KetonesThree ketone bodiesAcetone2%Acetoacetic acid20%Beta-hydroxybutyric acid78%Characteristic fruity breath acetone51Ketones:Normal Normal:negativeAbnormal:Inability to utilize carbohydratesExcessive loss of carbohydratesInadequate intake of carbohydrates52Ketones:MethodsReagent stripAcetest:tablet test53Ketones:MethodGlycine:also measures acetoneReagent strip:check package insertAcetest tablets:contain glycine54KetonesReagent stripSensitivity:5-10 mg/dlSpecificity:acetoacetic acid and/or acetoneFalse positive:highly pigmented urineFalse negative:improper specimen handlingAcetestSpecificity:acetoacetic acid and acetoneFalse positive:highly pigmented urienFalse negative:improper specimen handling55Blood:PurposeBlood in urine indicates pathologyTwo forms found in urineIntact RBCHemolyzed RBC56Blood:TermsHematuriaHemoglobinuriaMyoglobinuriaAll will give a positive blood reaction57Blood:Reagent stripTest can detect hemolyzed RBCHeme moiety imparts peroxidase activity and catalyzes the reaction58BloodSensitivitySpecificityIntact RBCHemolyzed RBC(hemoglobin)MyoglobinFalse positives:myoglobin,oxidizing agentsFalse negatives:ascorbic acid59Blood:Correlate reagent strip resultsMicroscopic findingsColor and clarity60Bilirubin and UrobilinogenBilirubin in urine is always pathologic:liver diseaseUrobilinogen in urine:normal to have a small amount:0.2 1.0 mg/dl61Three mechanismsPre-hepatic:liver is healthyHepatic:liver diseasePost-hepatic:liver is healthy,obstruction indicated62Bilirubin:MethodsReagent stripIctotest:tablet testFoam test63Bilirubin:MethodsReagent stripIctotest:tablet testSame reactionSame specificity:conjugated bilirubinFalse positive:urine colorFalse negative:low concentration,ascorbic acid,improper specimen handling64Bilirubin:MethodsReagent stripIctotest:tablet testSensitivity differsReagent strip:0.5 mg/dlIctotest:0.05 0.1 mg/dl 65Bilirubin:MethodsPossible to have a negative reagent strip test and positive ictotestDifference in sensitivity levelsAlways perform Ictotest whenUrine bilirubin test specifically orderedUrine appearance is amber:even if bilirubinreagent strip test is negativePositive reagent strip test66Bilirubin:Foam TestShake urine and observe resulting foamYellow foam=bilirubin67Urobilinogen:MethodsReagent strip testTwo reactions dependent upon manufacturerPara-dimethylaminobenzaldehydeDiazonium saltCannot determine absence of UBGWatson-Schwartz assay68Urobilinogen:MethodsPara-dimethylaminobenzaldehydeSensitivity:0.2 mg/dlSpecificity:False positive:any Ehrlich reactive compound;color masking;urine at body tempFalse negative:improper specimen handlingDiazonium saltSensitivity:0.4 mg/dlSpecificity:reacts only with UBGFalse positive:color maskingFalse negative:improper specimen handling69Urobilinogen:Watson SchwartzClassic method used to differentiateurobilinogen from porphobilinogen using adifferential extraction methodPara-dimethylaminobenzaldehyde70Nitrite:PurposeBacteria that contain a specific enzyme can reduce dietary nitrates to nitritesRapid screening test for UTI71Nitrite:NormalNormal:negativeAbnormal:Cystitis:bladderPyelonephritis:kidney72Nitrite:MethodReagent strip testNitrite+aromatic amine diazonium saltDiazonium salt+aromatic compound pink colorSensitivity:0.06-0.1 mg/dl nitrite 10,000 organisms73Nitrite:MethodReagent strip testSpecificity:False positive:improper specimen handling;color maskingFalse negative:bacteria cannot reduce nitratesBladder time not sufficient:need 4 hoursLow nitrite levelsAscorbic acidAntibiotic inhibition of bacteriaFurther reduction of nitrites to nitrogen74Leukocyte Esterase:PurposeIncreased WBC in urine is pathologicIndicates inflammation,infectionNeutrophils most common type of WBC found in urineCan detect intact WBC and lysed WBC75Leukocyte Esterase:NormalNormal:negativeAbnormal:Bacterial infection:cystitis,pyelonephritis,urethritisNon-bacterial infection:yeast,trichomonas76Leukocyte Esterase:MethodReagent strip:Granules in cytoplasm of WBC contain an enzyme(esterase)Ester esterase aromatic compoundAromatic compound+diazonium salt Purple colored complex77Leukocyte EsteraseSensitivity:5-15 WBC/hpfSpecificity:False positive:vaginal contamination;color maskingFalse negative:strong oxidizing agents(bleach);lymphocytes(no granules)7879谢谢你的阅读v知识就是财富v丰富你的人生41、学问是异常珍贵的东西，从任何源泉吸收都不可耻。阿卜日法拉兹42、只有在人群中间，才能认识自己。德国43、重复别人所说的话，只需要教育；而要挑战别人所说的话，则需要头脑。玛丽佩蒂博恩普尔44、卓越的人一大优点是：在不利与艰难的遭遇里百折不饶。贝多芬45、自己的饭量自己知道。苏联