The D Criteria for Rheumatoid Factor in Cardiac Disease?

There is a pretty high rate of positive rheumatoid factor in patience with ento carditus. Some schools of thought that would say, no, you can't. Am i obligated to get a transsophigial echo in patience with stafforius bactorimia, even with kind of a lower pretest probability? That's an area of debate. I think there are some situations where i would be ok with giving a getting a transe thoracic echo.