Test (ETCO_{c}) | Disease | |||
---|---|---|---|---|

Positive (120) | Negative (1250) | |||

Positive | True Positive (TP) (92) | False Positive (FP) (615) | TP + FP (707) | PPV 92/707 = 13.0% |

Negative | False Negative (FN) (28) | True Negative(TN) (635) | FN + TN (663) | NPV 635/663 = 95.8% |

TP + FN (120) | FP + TN (1250) | |||

Sensitivity 92/120 = 76.7% | Specificity 635/1250 = 50.8% |

Sensitivity = TP/TP + FN, the probability of the test finding disease among those who have the disease or the proportion of those with the disease who have a positive test result.

Specificity = TN/TN + FP, the probability of the test finding no disease among those who do not have the disease or the proportion of those free of the disease who have a negative test result.

PPV = TP/TP + FP, the percentage of people with a positive test result who actually have the disease.

NPV = TN/FN + TN, the percentage of people with a negative test result who do not have the disease.