I would imagine that active cancer cells would show up in a liquid biopsy, as it can detect active minimal residual disease. Note that dormant cells hiding in tissues often go completely undetected blood biopsies. As far as blood tests go, ca markers go up and down, due to the presences of cancer, inflammation, or the shedding of cancer cells (from chemo therapy). In active treatment, CT scans can only detect solid tumors. So, if CT scans show NED, it is still possible that cancer cells are circulating in the blood, but not always. My blood tests have shown CA 125 to fluctuate, but still in the normal range. CA 19-9 and 15-3 top the normal range but not in the 1000s; the doctors doesn't know what's causing this. I don't see any use in pinning my hope on either method of blood draw; as I understand it, my stage 3C serous cell cancer is incurable and hence can only be dealt with systemically. I don't know how cancer is dealt with if found only in the blood. Does anybody have information on this?