▁of ▁Ep C AM - pos itive ▁cells ▁as ▁a ▁tool ▁for ▁early ▁diagn osis ▁is ▁not ▁optimal . ▁ ▁Phys ical ▁methods ▁Phys ical ▁methods ▁are ▁often ▁filter - based , ▁en abling ▁the ▁capture ▁of ▁C TC s ▁by ▁size ▁rather ▁than ▁by ▁specific ▁ep it op es . ▁ ▁Screen Cell ▁is ▁a ▁fil tr ation ▁based ▁device ▁that ▁allows ▁sensitive ▁and ▁specific ▁isol ation ▁of ▁C TC s ▁from ▁human ▁whole ▁blood ▁in ▁a ▁few ▁minutes . ▁ ▁Per i pher al ▁blood ▁is ▁drawn ▁and ▁processed ▁within ▁ 4 ▁hours ▁with ▁a ▁Screen Cell ▁isol ation ▁device ▁to ▁capture ▁C TC s . ▁The ▁captured ▁cells ▁are ▁ready ▁for ▁cell ▁culture ▁or ▁for ▁direct ▁character ization ▁using ▁View R NA ▁in ▁situ ▁hy brid ization ▁ass ay . ▁The ▁Par sort ix ▁method ▁separ ates ▁C TC s ▁based ▁on ▁their ▁size ▁and ▁de form ability . ▁ ▁Hy brid ▁methods ▁Hy brid ▁methods ▁combine ▁physical ▁separation ▁( by ▁grad ients , ▁magnetic ▁fields , ▁etc .) ▁with ▁ant ib ody - medi ated ▁cell ▁retr ieval . ▁An ▁example ▁of ▁this ▁is ▁a ▁sensitive ▁double ▁gradient ▁cent rif ug ation ▁and ▁magnetic ▁cell ▁sorting ▁detection ▁and ▁enumer ation ▁method ▁which ▁has ▁been ▁used ▁to ▁detect ▁circul ating ▁ep ith el ial ▁cancer ▁cells ▁in ▁breast ▁cancer ▁patients ▁by ▁negative ▁selection . ▁The ▁principle ▁of ▁negative ▁selection ▁is ▁based ▁on ▁the ▁retr ieval ▁of ▁all ▁blood ▁cells ▁by ▁using ▁a ▁panel ▁of ▁ant ib od ies ▁as ▁well