M0175 overpayments come about when home health agencies fail to mark all the correct responses to the OASIS item on prior inpatient stays. If they mark that the patient had a rehab or skilled nursing facility discharge without also marking that the patient had a hospital discharge in the 14-day time period prior to admission, the episode receives an extra point in the service utilization domain.
That extra point bumps the HIPPS code up from a "J" or "L" in the fourth position to a "K" (without therapy) or "M" (with therapy). That results in an extra $200 for a non-therapy patient and an extra $600 for a therapy patient.
Underpayments occur when the reverse happens--agencies mark a hospital stay without a rehab or SNF stay when one occurred. This is a common error when patients switch bed types within a hospital, experts note.
