定义 Circulating free DNA or Cell free DNA (cfDNA):循环游离DNA或者细胞游离DNA,释放到血浆中的降解的DNA片段. https://en.wikipedia.org/wiki/Circulating_free_DNA 基本属性 长度 Azad A A, Volik S V, Wyatt A W, et al. Androgen Receptor Gene Aberrations in Circulating Cell-Free DNA: Biom