Abstract: A rapid, simple, sensitive and reliable method for detecting fecal carcinoembryonic antigens in stool, indicative of the presence of the colorectal cancer is described. The invention is based on the discovery that previous methods of removing coarse and gelatinous materials from a stool and liquid mixture resulted in removing a significant amount of total CEA and CEA-like substances. By not removing or destroying or altering molecules smaller than 500,000 MW, in the process of preparing the stool sample to be examined, a significant portion of CEA and CEA-like substances will remain in the filtered liquid for detection.