Just did some more reading, and on their website I found this:
"Keep in mind that occult fecal blood can arise from a variety of GI tract conditions, including but not limited to:
* Bleeding ulcers (gastric or colonic)
* Excessive parasite activity
* Protein-losing enteropathy (PLE)
* Lesions caused by hard particles of feed or other ingested material
* Petechiation, hyperemias or lypomas
Additionally, a positive test result (especially Test H) can arise from extraneous sources, such as:
* After dentistry or exercise-induced pulmonary hemorrhage
* Mare ovulation
* Post-surgery bleeding "
So, like I said, not conclusive of ulcers at all!