The aim of this guidance document is to provide a short and user-friendly support to genetic testing laboratories. It is based on internationally harmonised basic concepts and terminology for quality assurance and control (QA/QC). Relevant terms of the International Organization for Standardization (ISO) and the International Vocabulary of Metrology (VIM) are explained and references to other expert texts are provided. The document includes discussion and clarification of several often misunderstood issues. It takes into account the current scientific knowledge and the existing technological capabilities. This document may be revised and constitutes a deliverable of th NoE EuroGentest.JRC.D.2-Reference material