本国际标准建议在进行分子测定前，在检查前阶段，对用于循环无细胞DNA（ccfDNA）检测的静脉全血标本进行处理，记录，储存和加工。本国际标准涵盖静脉采血管采集的标本。本国际标准适用于分子体外诊断检查，包括医学实验室进行的实验室开发测试。它还旨在由实验室客户，体外诊断开发人员和制造商使用，也适用于执行生物医学研究，生物银行和监管机构的机构和商业组织。 从供体采集血液后，CcfDNA谱可能发生显着变化（例如，从白细胞释放基因组DNA，ccfDNA断裂和ccfDNA量变化）。因此，为确保ccfDNA检查和储存的优质血液样本，必须采取特殊措施。 需要采取不同的专门措施来保存血液基因组DNA，这在本国际标准中没有描述。血液基因组DNA被覆盖在ISO 20185-2，分子体外诊断检查 - 前期规范

This document provides recommendations and requirements on the handling, storage, processing and documentation of venous whole blood specimens intended for circulating cell free DNA (ccfDNA) examination during the pre-examination phase before an analytical test is performed. This document covers specimens collected in venous whole blood collection tubes. This document is applicable to any molecular in vitro diagnostic examination performed by medical laboratories. It is also intended to be used by laboratory customers, in vitro diagnostics developers and manufacturers, biobanks, institutions and commercial organizations performing biomedical research, and regulatory authorities. Different dedicated measures are taken for stabilizing blood genomic DNA, which are not described in this document. Blood genomic DNA is covered in ISO 20186-2. Different dedicated measures are taken for preserving DNA in circulating exosomes, which are not described in this document. NOTE ccfDNA obtained from blood by the procedures cited in this document can contain DNA originally present in exosomes[8][9]. DNA in pathogens present in blood is not covered by this document.