Use of genetic tests in the clinical practice setting is a current reality, and an increasing number of patients are asking about and requesting genetic testing. The push to translate genetic research findings and technological innovations into clinical practice will continue as our understanding of the genetic basis of disease increases. Special consideration is required when ordering genetic tests, beyond that of other laboratory tests, and an understanding of the unique aspects involved will help optimize clinical outcomes. The purpose of this primer is to provide a basic understanding of genetic testing, discuss current issues related to the use of tests, and outline practical steps for critically using genetic tests in clinical practice.