DiagAccuracy
Diagnostic Accuracy Study Workbench
2×2 Table
ROC Curve
Sample Size
Inter-rater Kappa
QUADAS-2
2×2 Contingency Table
Enter counts from your diagnostic accuracy study
STUDY NAME (optional)
Disease +
Disease −
Test +
Test −
Example: CT-PA for PE
Example: US Appendix
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Results
Enter values in the 2×2 table to calculate statistics
ROC Curve Builder
Add sensitivity/specificity pairs at different thresholds
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Curve Statistics
Add at least 3 points
ROC Curve
Sample Size for Diagnostic Accuracy
Target Sensitivity (%)
Target Specificity (%)
Desired 95% CI Half-width (%)
Margin of error — typically 5%
Expected Disease Prevalence (%)
Significance Level (α)
0.05 (z = 1.96)
0.01 (z = 2.576)
0.10 (z = 1.645)
Sample Size Results
Cohen's Kappa — Inter-rater Agreement
For binary ratings (e.g. positive/negative) between two readers
Reader 2: Pos
Reader 2: Neg
Reader 1: Pos
Reader 1: Neg
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Kappa Results
Enter agreement table to calculate kappa
Kappa Interpretation Scale (Landis & Koch)
QUADAS-2 Quality Assessment
Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2)
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