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Fecal Occult Blood Testing

Which Test?

Soft Indications for FOBT Use?

Slide 21

October 2011

There are other potential or “soft” indications for use of fecal blood testing, but these are not supported by evidence and have not been addressed in formal guidelines. For example, what about the value of fecal blood testing in patients with dark stools? The most important action in such circumstances is to assess the hematologic and hemodynamic status and let these parameters direct management decisions. Guaiac testing can be misleading, as causes other than bleeding (such as iron ingestion) can lead to both black stools and positive guaiac reactions. Furthermore, reducing agents (like vitamin C) can cause false negatives in face of elevated blood levels. Fecal blood testing may be reasonable if the patient is stable and a lab-based test, such as HemoQuant, would be best choice. In those with GI symptoms, some have advocated that use of fecal blood testing will help identify those with organic etiologies. However, studies addressing this application have shown that the positive predictive value is minimally affected and this practice has generally not been advised.

Soft Indications for FOBT Use?


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