An artificial plasma sample was prepared by spiking EVs from a male HCC cell line (e.g., HepG2) into plasma from a female healthy donor, and RT-ddPCR was adopted to count the copy numbers of the target SRY and the reference C1orf101 transcripts (encoded on Chromosome Y and Chromosome 1, respectively) for distinguishing and quantifying the spiked HCC EVs. The gene discussed is CATSPERE; the disease is hepatocellular carcinoma.