With the addition of the MDS item O0420, Distinct Calendar Days of Therapy, last October, there is an increase in situations when a short-stay assessment may be appropriate.  Prior to October 1, 2013, a total of five days of therapy across disciplines resulted in a Rehab Medium RUG group. Many scenarios that met some of the requirements for short-stay payment grouped into Rehab Medium because the previous RUG grouper added days from each discipline together. 

With the addition of distinct calendar days to the MDS, a Rehab Medium RUG group only will be achieved with five different days of treatment (must be 15 minutes of a discipline to qualify for a day of therapy). This has led to more frequent evaluations of whether short-stay requirements are met and some questions related to this assessment. Situations in which short-stay payment may apply include hospital readmissions or discharges home or to another facility in less than eight days, whether planned or unplanned.

The eight conditions that must be met for a short-stay assessment are clearly documented in Chapter 6 of the RAI Manual (pp. 6-17 – 6-21) and summarized below:

  1. The assessment must be a Start of Therapy OMRA (Other Medicare Required Assessment).
  2. A PPS 5-day or readmission/return assessment has been performed.
  3. The ARD (Assessment Reference Date) of the Start of Therapy OMRA must be on or before the 8th day of the Medicare stay.  
  4. The ARD of the Start of Therapy OMRA must be the last day of the Medicare Part A stay.
  5. The ARD of the Start of Therapy OMRA may not be more than 3 days after the start of therapy date not including the start of therapy date.
  6. Rehabilitation therapy started during the last 4 days of the Medicare Part A covered stay.
  7. At least one therapy discipline continued through the last day of the Medicare Part A stay.
  8. The RUG group assigned to the Start of Therapy OMRA must be Rehabilitation Plus Extensive Services or a Rehabilitation Group.

Questions may still arise when a scenario appears to meet the conditions, but an assessment does not have a rehab RUG group assigned. In reviewing the MDS, there are several areas to check related to short stay requirements.  

First, is the Start of Therapy assessment checked in A0310C?  This seems obvious but is sometimes overlooked.  (The short-stay assessment is the exception to the Start of Therapy requirement that an ARD be set on days 5 – 7 after the start of therapy.) Next, if there is not a 5-day scheduled assessment or readmission/return assessment checked in A0310B, has this already been done?

A number of dates in the MDS can affect the short-stay assessment. In Section A, there is Discharge Date (A2000), Assessment Reference Date (A2300) and End date of most recent Medicare stay (A2400C). 

For a patient who is discharged from the facility by the required eighth day, all of these dates must be the same. If a patient remains in the facility, the ARD and end of Medicare stay dates in A2300 and A2400C must be the same. In MDS Section O, the therapy end date in O0400A6, O0400B6 or O0400C6 for ST, OT or PT respectively must be the same as the end of Medicare stay date in A2400C or have a dash if therapy did not end. At least one therapy discipline must continue until discharge or be planned to continue. Providing therapy on the day of discharge is not a requirement if the plan was to continue therapy services. 

The start of therapy date (O0400A5, O0400B5 or O0400C5) needs to be considered as well.  One condition of a short-stay assessment is that therapy started in the last four days.  The day of a therapy evaluation counts as day one even if no treatment is provided.  If multiple disciplines are involved, the day of the earliest evaluation is day one. When the number of days a therapy is provided is more than four, short-stay criteria are not met. 

In the example below, a patient was admitted on April 25th and had a PT evaluation on that day.  The patient had PT treatments on April 25, 26 and 28 and was discharged unexpectedly to the hospital on April 29. The ARD must be on the last day of the stay. Because therapy did not start during the last four days, the assessment cannot be a short stay. This example also illustrates the condition that an ARD may not be more than three days after the start of therapy date.

4/25 – Admission




4/29 – Discharge

PT evaluation


PT treatment

PT treatment

PT treatment

Day 1

Day 2

Day 3

Day 4

Day 5

Whenever a patient has a Medicare stay of eight days or less and has therapy services, the possibility of a short-stay assessment should be evaluated. The Medicare Short Stay Assessment Algorithm on pages 6 to 20 of the RAI Manual is quick reference tool for checking the requirements for this assessment.

Jan White is the Senior Clinical Reimbursement Consultant at Post Acute Consulting