What the clinician needs to know about laboratory analyses of circulating tumor DNA

Liquid biopsies offer the possibility to evaluate cancer patients using noninvasive approaches. Circulating cell-free DNA (ccfDNA) is 1 of the most used and promising sources. Detecting tumor DNA among ccfDNA (ctDNA) can be used for early cancer detection, treatment response assessment, prognosis, and predictive evaluations. Providing analyses that can increase the quality of patient treatment is very much a joint effort between laboratory scientists and clinicians. With its use approaching clinical practice, it is important for clinicians to be familiar with the basic concepts and analyses behind ctDNA results in a similar way as laboratory scientists should have knowledge of the clinical needs to provide relevant analyses. In this Perspective, we describe the whole process of ctDNA analyses, from the preanalytical standards to reporting/analyzing results, and highlight some important factors that need to be addressed in the process of implementing them to clinical practice.