In this video, Dr. Sunil Dargar, MBBS, MD, Pathologist, New Delhi, will talk how reliable is stool occult blood In a stool sample, the occult blood is the second most frequently asked test in a stool sample. Occult blood is the presence of blood in stools but not visible to the naked eye. The occult blood comes from the upper area of the intestines. The patient is instructed to avoid non-veg food for 48 hours before the test. Also any iron related drugs should be avoided before the collection of the sample. Dr. Dargar also talks about the importance of checking two samples for occult blood from the same stool sample of the patient as occult blood is not uniformly present.