A MODIFIED ROC ANALYSIS FOR THE SELECTION OF CUTOFF VALUES AND THE DEFINITION OF INTERMEDIATE RESULTS OF SERODIAGNOSTIC TESTS
A MODIFIED ROC ANALYSIS FOR THE SELECTION OF CUTOFF VALUES AND THE DEFINITION OF INTERMEDIATE RESULTS OF SERODIAGNOSTIC TESTS
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DOI：
10.1016/0022-1759(95)00121-p
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发表时间：
1995-09-11
影响因子：
2.2
通讯作者：
GOBEL, P
中科院分区：
文献类型：
--
作者：
GREINER, M;SOHR, D;GOBEL, P
采用ELISA方法对50份临床确诊犬伯氏疏螺旋体感染病例血清和44份阴性对照血清进行了伯氏疏螺旋体特异性抗体检测。将数据提交给“双图接收者工作特征”（TG-ROC）分析，该分析是检测灵敏度（Se）和特异性（Sp）相对于阈值（截止值）的图，假设后者是一个自变量。因此，与传统的ROC分析相反，有效的Se和Sp对可以直接从TG-ROC图中读取预先指定的阈值。可以得到实现相等测试参数(Se = Sp = theta（0) (theta- 0)）的截止点作为两个图的交点。由于theta(0)的值低于预先选定的精度水平（95%或90%），因此选择两个截止值来表示“中间范围”（IR）的界限。IR可被视为临床解释检测结果的“边缘”范围。给出明确测试结果的测量范围（MR）的比例可以使用IR表示为“有效范围比例”（VRP = (MR - IR)/MR）。VRP和θ(0)是测试比较的有用参数，因为它们不依赖于单个截止点的选择。此外，截断值的选择还通过效率、约登指数和似然比的图形显示来支持，这些图形显示可以视为预先指定的截断值的函数。TG-ROC是作为商业上可用的电子表格程序（MS-EXCEL, Microsoft）的用户定义模板派生的。
A total number of 50 sera from clinically confirmed cases of canine Borrelia (B.) burgdorferi infection and 44 negative control sera were tested with a B. burgdorferi specific antibody ELISA. The data were submitted to the 'two-graph receiver operating characteristic' (TG-ROC) analysis which is a plot of the test sensitivity (Se) and specificity (Sp) against the threshold (cut-off) value assuming the latter to be an independent variable. Thus, in contrast to the conventional ROC analysis, valid pairs of Se and Sp can be read for pre-assigned threshold values directly from the TG-ROC plots. A cut-off that realises equal test parameters (Se = Sp = theta(0) (theta-zero)) can be obtained as the intersection point of the two graphs. Since the value for theta(0) is below a preselected accuracy level (95% or 90%), two cut-off values are selected that represent the bounds of an 'intermediate range' (IR). IR can be considered as a 'borderline' range for the clinical interpretation of test results. The proportion of the measurement range (MR) that gives unambiguous test results can be expressed using IR as the 'valid range proportion' (VRP = (MR - IR)/MR). VRP and theta(0) are useful parameters for test comparison since they do not depend upon the selection of a single cut-off point. In addition, the selection of cut-off values is supported by graphical displays of efficiency, Youden's index and likelihood ratios which can be considered as functions of the pre-assigned cut-off value. TG-ROC was derived as a user-defined template for a commercially available spreadsheet programme (MS-EXCEL, Microsoft).