International society of liquid biopsy (ISLB) perspective on minimal requirements for ctDNA testing in solid tumors

Circulating tumor DNA (ctDNA) testing has transformed precision oncology by enabling the non-invasive detection of actionable mutations. To facilitate broader clinical adoption and improve testing accuracy, standardized quality criteria must be clearly defined and universally implemented. The International Society of Liquid Biopsy (ISLB) established the Quality Control and Accreditation Committee to develop consensus-based minimal standards for ctDNA analysis in oncology. Ensuring reliable and reproducible ctDNA testing necessitates standardization across the pre-analytical, analytical, and post-analytical phases. Key considerations include appropriate blood collection, efficient cfDNA isolation and purification, thorough assay validation, and precise data interpretation. The ISLB is committed to leading collaborative efforts among laboratories, regulatory bodies, and professional organizations to advance standardization and ensure high-quality ctDNA testing worldwide. Through initiatives led by the Quality Control and Accreditation Committee, educational programs, and multidisciplinary stakeholder workshops, ISLB provides a structured framework to promote standardization and foster innovation. By addressing current challenges and advocating for robust quality standards, ctDNA testing can reach its full potential in advancing personalized cancer care, enabling more precise and timely interventions for patients. This manuscript provides the first global initiative for quality control in liquid biopsy, presenting the ISLB perspective on minimal requirements for ctDNA testing in solid tumors.