The report released Monday includes a list provided by SageWest, which the hospital said included all known instances of patients exposed to dirty instruments. But the dates provided by SageWest do not match the dates noted in the previous health department investigations.

The SageWest list “is likely an underestimation of the true incidence of bioburden on surgical instruments at (SageWest) because documentation of these events is poor,” the report states.

The report also notes that it was unlikely surgeons caught every instance of dirty surgical tools being used.

“If bioburden was getting through decontamination, it is likely there were other events that went unnoticed,” the report states.

In an October report, a hospital employee told health department investigators that no follow-up was conducted after a surgical instrument brought to an operating room for surgery was found to have dried blood on it because the instrument did not touch the patient.

But Monday’s report noted that “even if the instrument never touches the patient, the presence of instruments with bioburden can contaminate the surgical field.”

SageWest interim COO Betty Brown stressed in an interview that no patients had been harmed.