Fecal sample processing and analysis comprising detection of blood
A method of processing a fecal sample from a human subject comprising removing a portion of a collected fecal sample and adding the removed portion of the sample to a buffer that prevents denaturation or degradation of blood proteins found in the sample, and detecting the presence of human blood in the removed portion of the fecal sample. The method further comprises stabilizing the remaining portion of the fecal sample.
1. A method of processing a freshly-collected fecal sample without freezing, the method comprising:
a) collecting a fecal sample from a human subject, wherein the fecal sample is collected at home by the human subject by defecation directly into a sealable collection vessel;
b) removing a portion of said fecal sample to a separate container to produce a removed portion and a remaining portion of said fecal sample;
c) combining the removed portion in the separate container with a buffer that prevents denaturation or degradation of blood proteins found in a fecal sample; and
d) stabilizing the remaining portion of the fecal sample by adding a buffer that maintains DNA integrity in a fecal sample to the remaining portion in the sealable collection vessel.
2. The method of claim 1 , further comprising delivering the container containing the removed portion and buffer and the sealable vessel containing the remaining portion of the fecal sample and buffer to a medical diagnostics laboratory.
3. A method of processing a fecal sample, the method comprising:
A) obtaining a pair of portions of a fecal sample from a human subject, the pair of portions comprising a container containing a removed portion and a buffer, and a sealable vessel containing a stabilized remaining portion of a fecal sample and a buffer obtained by the method of claim 1 ;
B) testing the removed portion of said fecal sample for a concentration of hemoglobin present in said removed portion;
C) extracting DNA from the remaining portion of said fecal sample; and
D) analyzing said DNA for the presence of DNA from the human subject having an epigenetic modification.
4. The method of claim 3 , wherein testing for the concentration of hemoglobin in said removed portion comprises immunochemical detection of hemoglobin.
5. The method of claim 3 , wherein the removed portion of said fecal sample is considered positive for the presence of blood when the concentration of hemoglobin detected in said removed portion is at least 5 ng/ml.
6. The method of claim 3 , wherein the removed portion of said fecal sample is considered positive for the presence of blood when the concentration of hemoglobin detected in said removed portion is at least 10 ng/ml.
7. The method of claim 3 , wherein the removed portion of said fecal sample is considered positive for the presence of blood when the concentration of hemoglobin detected in said removed portion is at least 20 ng/ml.
8. The method of claim 3 , wherein the removed portion of said fecal sample is considered positive for the presence of blood when the concentration of hemoglobin detected in said removed portion is at least 50 ng/ml.
9. The method of claim 3 , wherein the removed portion of said fecal sample is considered positive for the presence of blood when the concentration of hemoglobin detected in said removed portion is at least 200 ng/ml.
10. The method of claim 3 , wherein said epigenetic modification comprises aberrant methylation.
11. The method of claim 3 , wherein said aberrant methylation comprises hypermethylation.
12. The method of claim 3 , wherein said DNA from the human subject comprises a gene and/or a promoter region of a gene.
13. The method of claim 12 , wherein said gene is selected from the group consisting of PHACTR3, NDRG4, FOXE1, GATA4, GPNMB, TFPI2, SOX17, SYNE1, LAMA, MMP2, OSMR, SFRP2, and CDO1.
14. The method of claim 10 , wherein analyzing said DNA comprises modifying said DNA with bisulfite ions under conditions wherein unmethylated cytosine is converted to uracil.