Sensitivity and false negatives — FRCA Primary MCQ

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HardStatistics and EBMSensitivity and false negativesFRCA Primary

A difficult-airway score has sensitivity 0.84 and specificity 0.88 at its chosen threshold. What is the positive likelihood ratio at that threshold?

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Correct answer: C — 7.0

The best answer is “7.0”. The positive likelihood ratio is sensitivity divided by one minus specificity: 0.84/(1−0.88)=0.84/0.12=7.0. This expresses how much more likely a positive result is in a patient with the outcome than without it; it is not sensitivity, predictive value or the odds ratio.

Reference: Corbacioglu and Aksel, ROC curve analysis in diagnostic accuracy studies: https://pmc.ncbi.nlm.nih.gov/articles/PMC10664195/