A method of processing a fecal sample from a human subject comprising combining a first portion of a collected fecal sample with a stabilizing buffer that maintains DNA integrity in a fecal sample, and combining a second portion of the sample with a solution that prevents denaturation or degradation of blood proteins found in a fecal sample. Embodiments comprise testing DNA extracted from the first portion of the fecal sample for the presence of a human DNA, and testing the second portion of the fecal sample for the presence of human blood.