ER also did an upper and lower Gl. No occult blood in her stool.

ER also ran an upper and lower Gl. No occult blood in her stool.

Even if there is an occult blood cancer, you wouldn't expect interferon to make it worse.

Amend the beginning of the paragraph to read as follows: "Dried blood spots, collected by applying a drop of blood onto absorbent material, or faecal occult blood screening tests and blood or blood components…".