Locum tenens is a confusing situation in the case where a physician takes a vacation or otherwise isn’t available and hires a physician to see patients on site, Medicare can deny the claim unless it is properly documented. The reason is that Medicare is very strict about seeing specific modifiers on medical billing claims that involve a substitute or locum tenens physician. Further, your medical billing claim must have the time limits observed for locum tenens doctors. Otherwise, Medicare won’t pay for their services rendered to patients. Also, you can’t hire a locum tenens as extra staff. This includes situations where the regular attending physician goes on vacation, has an …