I have simple model for some medical test characteristics calculation.
- $D+$= Disease present
- $T+$= Test positive (yes\no)
$P(D+)$ is very small (0.000001).
The problem is I don't know what the probability of Test being positive in the general population. This is a very new test and we don't know the exact profile of this very expensive test yet.
Test result can be affected by many factors. Given this problem definition, how can I incorporate these many factors that may change the test result (cause a false positive or a false positive) into my general basic Bayesian model below?
My model is $P(T+|D+) = P(D+|T+)P(D+) / P(D+)$