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1、 肾功能检验肾功能检验执教教师:XXXAnatomy of KidneyFunctions of the kidneyExcretion of Metabolite Waste: urea, uric acid, creatinineUrine Production, regulation of homeostasis, water, acid base balanceEndocrine Function: renin, erythropoietin, 1,25 -dihydroxycholecalciferolRenal function testsDetect renal damageMo
2、nitor functional damageDistinguish between impairment and failureKidney FunctionA plumbers viewHow do you know its broken?NO Urine!Clinical symptomsTestsWhere can it break?Pre-renalRenalPost-renalLaboratory tests of renal functionGlomerular Function TestsRenal Tubular Function TestsSection 1 Investi
3、gation of Glomerular FunctionRenal Blood Flow: 1200-1400ml/minRenal Plasma : 600-800ml/min20% of plasma: glomerular filtration GFR:Glomerular Filtrtion Rate Concept Renal CleranceConcept Virtual volume of plasma from which the substance in question has been completely removed during a given time int
4、erval. C=UV/P U:urine concentrtion P:plasma con. V:urine flow rateUsefulness of Renal CleranceFreely filtrated, neither secreted, nor reabsorbed: Inulin: GFR DeterminationFreely Filtrated, small amounts secreted, without reabsorption: Cretinine:GFRFree filtrated, completely reabsorption: Glucose Tub
5、ular Maxima Reabsorption RateInulin ClerancePolymer of fructoseMW:5500Free filtration, without secretion and reabsorptionGFRMethod Reference Interval: 2.0-2.3ml/minEndogenous Creatinine Clearance100g,98% stored in musle,MW:113Cretine phosphate-cretinecretinineFreely filtration, small mounts: secreti
6、onExogenous and Endogenous CreatinineGrossly Investigate the GFRMethod 24h urine collection method modified 4h urine collection method Clerance Correction: Ccr x SBSA/IBSAPlasma ureaSecreted and reabsorbed by tubules, freely filtratedquick, simple measurementwide reference range 3 - 8 mmol/Lsensitiv
7、e but non-specific index of illnessUrea excretionfiltered at glomerulusabout 40% filtered urea is reabsorbed by renal tubules in healthmore urea is reabsorbed if rate of tubular flow is slowtubular flow rate is slow when there is renal hypoperfusionIncreased plasma ureaGI bleedtraumarenal hypoperfus
8、iondecreased RBFdecreased ECFVacute renal impairmentchronic renal diseasepost-renal obstructioncalculustumourUreaUseful test but must be interpreted with great careAlways consider input, output and patients fluid volumePlasma creatinine50 - 140 umol/Lincreases in concentration as GFR decreasesanalyt
9、ical interferences (acetoacetate - DKA)NOT proportional to renal damagePlasma CreatinineGFRGFRpCreatpCreat140 mL/min140 mL/min0 mL/min0 mL/minChange within an Change within an individual patient is individual patient is usually more important usually more important than the absolute valuethan the ab
10、solute valuePlasma creatinine in chronic renal disease May increase to 1000 umol/LPlot of recipricol of plasma creatinine concentration predicts when intervention is required in end stage renal failureTimeTime1/ pCreat1/ pCreatPlasma Uric Acid20%:foods;80%:purine metabolismSmall amounts: conjugated
11、with albuminFree Filtrated,98%-100%:reabsorbedPlasma UA concentration: depend on glomerular filtration and tubular reabsorptionProgression of chronic renal diseasePlasma Cystatin CCysteine proteinase inhibitorProduced by nucleated cellsMW:13000, free filtration,reabsorbed and metabolized by tubulesP
12、lasma CysC concentrtion: depend on glomerular filtrationCarbamylated hemoglobinUreabloodcyanateHb carbamylatedCarHbARF:no changes(1 weeks)CRF: increaseLaboratory tests of renal functionglomerular filtration rate impracticalcreatinine clearance unreliableplasma creatinine specific but insensitiveplas
13、ma urea subject to problemsurine volume often forgotten!Section 2 Investigation of Tubular FunctionDistal nephron Function tests 1. Mosenthal test Concentration dilution test 8 AM :Voiding and Discarded 10,12,14,16,18,20:00 and 8:00 next day: collecting urine samples Determing the urine volume and g
14、ravity2.Urine Osmolarity3.Acute Oliguria Prenal? Renal?Proximal tubular Function tests 1.Low MW proteins in urine 2.Tubular maximal glucose reabsorption 3.Tubular maximal PAH secretion 4.Amino acide in urine Fanconi SyndromeSection 3 Effective Renal Blood FlowIsotope Method:131I-OIHPAH Clearance: 20
15、%:filtrated,80%:secreted by tubulesSection 4 Investigation of renal tubular acidosisTubular Acidosis:I,II,III.IVI:distal formII:proximal formNH4Cl Loading TestOral administration of NH4ClArtificial Metabolic AcidosisUrine Sample CollectionpH determinationFraction of HCO3- excretionHCO3-:85-90%: reabsorbed by proximal tubules; 10-15%: reabsorbed by distal tubulesOral Administration of NaHCO3Urine CollectionDetermination of PCr,UCr,PHCO3,UHCO3Caculation: FEHCO3=UHCO3.PCr/UCr.PHCO3谢谢观看请指导