Flashcards in Classes 26-28 Screenings in Medicine Deck (24)

Loading flashcards...

1

## True Positive (TP)

###
Test correctly reports a positive result in a patient that actually does have the disease

(Box A)

2

## True Negative (TN)

###
Test correctly reports a negative result in a patient that actually does not have the disease

(Box D)

3

## False Positive (FP)

###
Test incorrectly reports a positive result in a patient that actually does not have the disease

(Box B)

4

## False Negative (FN)

###
Test incorrectly reports a negative result in a patient that actually does have the disease

(Box C)

5

## Sensitivity

###
How well a test can detect presence of disease when in fact disease is present -- Positivity-of-test in the diseased

Proportion of time that a TEST is positive in a patient that does have the disease

6

## Sensitivity equation

###
Sensitivity = TP/(TP + FN) x 100%

Sensitivity = TP/(all Diseased) x 100%

7

## A highly sensitive test has:

### A low false negative rate

8

## Specificity

###
How well a test can detect absence of disease when in fact the disease is absent -- Negativity-of-test in the healthy

Proportion of time that a TEST is negative in a patient that does not have the disease

9

## Equation for Specificity

###
Specificity = TN/(TN + FP) x 100%

Specificity = TN/(All not diseased) x 100%

10

## A highly specific test has:

### A low false positive rate

11

## Positive Predictive Value (PPV)

###
How accurately a positive test predicts the presence of disease

Percentage of TP's in patients with a positive test (correct prediction)

Also referred to a predictive value-positive (PVP)

12

## Equation for PPV

###
PPV = TP/(TP + FP) x 100%

PPV = TP/(All Positive Tests) x 100%

13

## Negative Predictive Value (NPV)

###
How accurately a negative test predicts the absence of disease

Percentage of TN's in patients with a negative test (correct prediction)

Also referred to as Predictive Value-Negative (PVN)

14

## Equation for NPV

###
NPV = TN/(TN + FN) x 100%

NPV = TN/(All Negative Tests) x 100%

15

## Diagnostic Accuracy (DA) or Diagnostic Precision (DP)

### Proportion of time that a patient is correctly identified as either having a disease or not having a disease with a positive or negative test, respectively

16

## Calculation for DA (or DP)

###
= (TP/TN) / (TP + FP + FN + TN) x 100%

= (TP/TN) / (All patients) x 100%

17

## Likelihood Ratio (LR)

### Probability of a given test result (positive or negative) for a person with the disease / probability of the same test result (+ or -) for a person without the disease

18

## Likelihood Ratio Positive (LR+)

### Probability of a positive test in the presence of disease / probability of a positive test in the absence of disease

19

## Equation for Likelihood Ratio Positive (LR+)

###
[(A/(A+C)) / (B/(B+C))]

Sensitivity/(1-Specificity)

20

## Likelihood Ratio Negative (LR-)

### Probability of a negative test in the presence of disease / Probability of a negative test in the absence of disease

21

## Equation for Likelihood Ratio Negative (LR-)

###
[(C/(A+C)) / (D/(B+D))]

(1-Sensitivity) / Specificity

22

## LR+ should be _____ to demonstrate the test is most beneficial.

### >10

23

## LR- should be _____ to demonstrate the test is most beneficial

24