Fecal analysis: occult blood

Overview

• Low grade intestinal hemorrhage may produce no visible color change (occult blood) in feces but chemical testing can detect hemoglobin products.

Uses

In combination

• With hematology : investigation of anemia    .
• Coagulation tests : investigation of anemia.
• With fecal screening    : investigation of diarrhea .
• Biochemistry : investigation of ulceration, ie liver, azotemia.

Result data

Abnormal values

• Intestinal neoplasia, hemangiosarcoma    (very rare in cats).
• Gastrointestinal ulceration .

Errors and Artifacts

• False negative : if using commercial kit specific for human hemoglobin.
• False positive :
• If animal is not deprived of hemoglobin + myoglobin-containing foods for at least 4 days before sampling.
• If blood licked from external wounds, swallowed from nasal lesion, or coughed up from lower respiratory tract.
• Feces can look black if on peptobismol or iron supplement.
• Cimetidine.

Sources

Publications

Refereed papers

• Tuffli S P, Gaschen F, Neiger R (2001) Effect of dietary factors on the detection of fecal occult blood in cats. J Vet Diagn Invest 13 (2), 177-179.
• Jinbo T et al (1998) Immunological determination of fecal hemoglobin in dogs. Vet Res Commun 22 (3), 193-201.
• Jinbo T et al (1997) Experimental detection of canine hemoglobin (occult blood) in canine feces by reversed passive latex agglutination. 21 (5), 347-353.