analysisandevaluationoftheevidenceofdiagnostictest(英文版)(編輯修改稿)
2025-03-28 08:51 本頁(yè)面
【文章內(nèi)容簡(jiǎn)介】 pound assay Sen Spe CPK 96 57 SGOT 91 74 LDH 87 91 91 Multivariate analysis ?SEN ?SPE single variable analysis marker methods SEN (%) spe (%) cutoff AREA a ELISA b ELISA c ELISA d ELISA e ELISA f ELISA multivariate analysis using logistic regression Combined markers SEN （％） SPE（％） AREA a and b a and c a and e a and f a and d .0936 b and c b and d b and e b and f C and d C and e C and f d and e d and f e and f Prediction the probability of a disease ? Logit(P)= + x a + x e Avoiding overfitting ? Overfitting occurs when a puter model identifies a “chance” pattern that discriminates cancer patients from noncancer patients, perfectly fitting that dataset but not reproducible in other data sets. ? One way to avoiding overfitting is to randomly split the data into separate training and test samples. The EBM steps for diagnostic tests ? Looking for the most suitable study papers according to the clinical question ? Bring forward the question in clinic ?Example 2 : if detection of serum forritin can diagnose Iron deficiency anemia? ? Search the puter information using the apposite key word ?“diagnose Iron deficiency anemia” and “diagnostic test” and “human” Evaluation of the scientificity of the papers ? If pared with the gold standard independently and blindly ? Example 2: Iron stain with myeloid biopsy ? If detected with the control test for every quizzee Gold standard Total （ No.） Results + New diagnostic test + 35 15 50 sensitivity=46% New diagnostic test 40 460 500 specificity=% Verification bias Gold standard Total （ No.） Results + New diagnostic test + 35 15 50 sensitivity=90% New diagnostic test 4 46 50 specificity=75% If the patient samples included a broad spectrum of the disease ? If the disease spectrum uniform ?What’s the objective question that the investigator concerned about ?If the study sample and the quizzee is uniform ?Spectrum bias： overstate the performance parameter of the diagnostic test because of excluding the “grey zone”
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