The invention discloses a
lung nodule diagnosis method based on
plasma DNA methylation characteristics and application, and the method comprises the following steps: S1, collecting
peripheral blood of a subject in a special cfDNA preservation tube, carrying out
centrifugal separation to obtain
plasma, extracting cfDNA by adopting an optimized paramagnetic
particle method or column extraction method, carrying out
quality control on the cfDNA, then carrying out thorough hydrosulphite conversion treatment on the cfDNA, and carrying out purification treatment on the cfDNA to obtain the
plasma; unmethylated
cytosine is converted into
uracil, and methylated
cytosine is kept unchanged. The invention is derived from the selection of an early and stable epigenetic marker of
DNA methylation, and replaces traditional dependent clinical parameters or
mutation signals appearing at a
late stage. According to the method, the problem of insufficient discrimination capability (AUClt; 0.60) caused by limited input information of an existing clinical prediction model (such as a MayoClinic model) is directly solved.