“Pharmacogenetics (PG) examines inherited or acquired variations in genes that dictate drug response, disposition, or toxicity and explores how these variations can be used to optimize medication therapy”…

Lab tests are done before the prescription; the CPOE alerts the doctor if the test is positive.

Perhaps an example of enhancing traditional CPOE/ePrescriing systems with personalised medicine?

Goldspiel BR, Flegel WA, DiPatrizio G, et al. Integrating pharmacogenetic information and clinical decision support into the electronic health record. May 1, 2014 2014;21(3):522-528.
http://jamia.bmj.com/content/21/3/522.full