The last ten years have seen a remarkable expansion and advancement of Molecular Diagnostics. Precision medicine has advanced thanks in large part to the adoption of new, very complicated tests and the integration of new technology into clinical molecular diagnostics laboratories. Infectious disease, genetics, pharmacogenomics, and oncology are just a few of the diverse domains that fall under the umbrella of molecular diagnostics; nonetheless, the fundamental principles and possible causes of inaccuracy are shared by all of these different applications. This article discusses typical mistakes that might happen when using diagnostic molecular tests. Similar to other clinical laboratory sections, a robust quality control and quality assurance programme is required for the identification of issues, the monitoring of errors, and the use of techniques to ensure quality.