Hi Yahia.
Just regular observations, and experience.
My knowledge of immunology really helps drive the theories along.
Some of the tests I have done, are not performed with any regularity among clinical techs, so I see things in a less restricted way.
I have have been witness to some pretty strange stuff. But, usually there is a basic path to take, and things will be familiar for the most part. I see repeats of the same conditions, and I see other things with are completely abnormal. Shroom