Exercise 1: Avian influenza - Test 1
You and your laboratory have developed an ELISA test for avian influenza (AI) virus and would like to evaluate it. Therefore you use the test on 300 experimentally infected chickens and 1000 chickens from a confirmed non-infected flock.
Scientist cleaning avian influenza transportation containers at the Bird Lab, Alaska Science Center, Anchorage, Alaska
Image source
You obtain the following results:
| AI + |
AI - | Total | |
| ELISA + |
294 |
25 |
319 |
| ELISA - | 6 |
975 |
981 |
| Total | 300 |
1000 |
1300 |
Calculate sensitivity, specificity and predictive values
Calculate both the sensitivity and specificity of the new test and the predictive values in your population (where the true prevalence is 300/1300 = 23.1%).
Type in the values (round to one number after decimal point, e.g. 99.9). User the calculator if required.
SE =
%
SP =
%
PPV =
%
NPV = %
Calculator: