診斷試驗(yàn)評(píng)價(jià)

案例討論

電話：4366351Email：01.Screeningtestoutcomes:Fordichotomous-positiveornegativeForcontinuous-categorizetopositiveornegativeIfscreeningtestfindingis:PositiveNegativeright:truepositivewrong:falsepositiveright:truenegativewrong:falsenegativePopulationrealityDiseaseNodiseaseTestresultsPositiveNegativeTruePositiveTrueNegativeFalseNegativeFalsePositiveSensitivity=Specificity=TPabilitytoidentifyTP+FNthosewithdisease

TNabilitytoidentifyTN+FPthosew/odiseaseResultofaDichotomousTest

withDiseaseStatusTruepositive(TP)=HavediseaseandhavepositivetestFalsepositive(FP)=Nodisease,buthavepositivetestFalsenegative(FN)=Havedisease,buthavenegativetestTruenegative(TN)=NodiseaseandhavenegativetestWithDiseaseW/ODiseasePopulationTestResultsPositiveNegativePredictiveValueofaTestIfthetestresultsarepositiveinthispatient,whatistheprobabilitythatthispatienthasthedisease?Whatproportionofpatientswhotestpositiveactuallyhavethediseaseinquestion?PositivePredictiveValueofaTest:PPV=

NegativePredictivevalue:

Withnegativeresult,whatistheprobabilitythatthepatientdoesnothavethedisease?

NPV=TruepositiveTotalpositiveTrueNegative

TotalnegativeRelationshipbetween

PredictiveValueandPrevalencePredictivevalueimprovesasprevalenceincreases.RelationshipbetweenPredictiveValueandSpecificityPredictivevalueimprovesasspecificityofascreeningtestincreases.IsLDL/HDLratiobetterthanLDL?Betterforwhat?ScreeningforType2Diabetes:StrongHeartStudyWang,DiabetesCare,2002.AreaunderthecurveofWaist,WHRandWHTR(WI)WHtROptimalthresholdsofWHTRfordefiningoverweightandobesityandcorrespondingsensitivityandspecificityinChineseboysandgirlsaged8-18years

CorrelationbetweenWHTRandBMIwithageWHTRBMI,kg/m2Age,yrsGirlBoysBoys:r=-0.108,p<0.001Girls:r=0.035,p<0.001

Boys:r=0.413,p<0.01Girls:r=0.39,p<0.001

例1某社區(qū)的人口為5萬(wàn)人，現(xiàn)擬用血糖試驗(yàn)來篩檢糖尿病。不同的篩檢標(biāo)準(zhǔn)及其準(zhǔn)確性見下表：?jiǎn)栴}1.按下面的情況，分別列出四格表，通過計(jì)算填入相應(yīng)的數(shù)字，并計(jì)算預(yù)測(cè)值。表4-2.血糖試驗(yàn)不同篩檢標(biāo)準(zhǔn)的準(zhǔn)確性篩檢標(biāo)準(zhǔn)（mg/dl)靈敏度（%）特異度（%）≥13081.482.4≥18050.099.8社區(qū)患病率為1.0%，篩檢標(biāo)準(zhǔn)為≥130mg/dl社區(qū)患病率為1.0%，篩檢標(biāo)準(zhǔn)為≥180mg/dl社區(qū)患病率為2.0%，篩檢標(biāo)準(zhǔn)為≥180mg/dl問題如果要在人群中篩檢肝癌，用這3種方法中的哪種收益會(huì)最大？如果某社區(qū)有50萬(wàn)人口，肝癌的患病率為20/10萬(wàn)，在該社區(qū)中用GGT-II來篩檢肝癌是，會(huì)造成多少假陽(yáng)性？陽(yáng)性預(yù)測(cè)值是多少？它表示什么？通過該案例，你得到什么啟發(fā)？聯(lián)合試驗(yàn)并聯(lián)兩項(xiàng)試驗(yàn)，任何一項(xiàng)陽(yáng)性就算陽(yáng)性串聯(lián)兩項(xiàng)試驗(yàn)，同時(shí)陽(yáng)性時(shí)才算陽(yáng)性問題請(qǐng)分別計(jì)