Blood that appears dark reddish brown to black and tarry in a fecal sample is partially:

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Quizplus · Accepted Answer

Dark reddish brown to black and tarry feces is a characteristic feature of melena which is caused by the digestion of blood in the gastrointestinal tract. Hemolysis is the breakdown of red blood cells which can contribute to the appearance of dark feces in this case. Icteric feces would have a yellow tinge due to the presence of bilirubin, lipemic feces would have a milky appearance due to the presence of fat, and polycythemia is an increase in the number of red blood cells which may result in the feces being darker in color but not specifically tarry.

Blood That Appears Dark Reddish Brown to Black and Tarry