Are your processes achieving accurate CMI reimbursement for the care that your staff delivers? The case mix index is intended to reflect the type of residents being treated and the level of care required. Therefore, it is important to ensure that procedures are in place to identify, document, and code the conditions present and services provided in order to receive appropriate reimbursement.

Case Mix Rosters

Depending on the individual state, case mix rates may be set every quarter to every six months to account for changes in the population and its acuity. Strong systems for managing due dates and verifying case mix roster accuracy are key. It’s important to know your state’s cut off dates for MDS assessment completion and transmission. Enter these dates on your electronic calendar with set reminders or keep a copy posted near your desk. Review case mix rosters for errors including payer source, correct assessment type, missing assessments, changes with or incorrect RUG and default days.


Errors and missed opportunities are more likely during staffing shortages and increased use of agency staffing; therefore, it is imperative to review ADLs during the look-back period for accuracy. If there are inconsistencies or changes noted, interview care staff and clarify the discrepancy if necessary. Consider whether a significant change MDS assessment or referral to therapy is needed.  Education with follow up monitoring may be needed using change of shift inservices or competency reviews focusing on one ADL topic a week beginning with late loss ADLs.

Hospital Records

Some MDS items delivered in the hospital (while not a resident), are factored into case mix RUG classifications. For example, the RUG-III 34 Grouper considers parental/IV, suctioning, tracheostomy care and IV medication while not a resident. The RUG-IV 48 Grouper for special care high includes parenteral/IV feeding while not a resident. Retrieving and reviewing hospital records, such as the MAR, prior to establishing the ARD should be a routine process for the MDS team.


The start of therapy is retrieved from MDS section O. For admissions, the rehab RUG begins on day 1 if criteria are met during the reference period. For quarterly and significant change assessments, the rehab RUG begins with the ARD. So, it is important to meet rehab criteria classification as soon as clinically indicated. Depending on the RUG grouper, a combination or distinct days is required for rehab classification.

Example Rehabilitation Classification

RUG-III 34 GrouperRUG-IV 48 Grouper
150 Minutes and 5 days or more (15 min per day minimum) in any combination of therapy in last 7 days OR150+ minutes and at least 5 distinct days of any combination of the 3 disciplines OR
45 Minutes and 3 days or more (15 min per day minimum) in any combination of therapy in last 7 days AND at least 2 nursing rehabilitation services45+ minutes and at least 3 distinct days of any combination of the 3 disciplines and 2 or more Restorative Nursing Services4 received 6 or more days

Physician and Nursing Documentation -Examples of Common Missed Opportunities

      • Physician (or other acceptable provider) documented diagnosis must be documented in the last 60 days and considered active during the reference period. For example, pneumonia would be considered active if identified by chest X-ray, documented signs and symptoms of pneumonia (i.e .cough, lung sounds, etc.), MD orders for treatment or therapy for functional limitations due to pneumonia.
      • For a resident that has a diagnosis of COPD or other chronic lung disease in MDS Section I6200, shortness of breath is a common symptom. Documentation needs to include if shortness of breath or difficulty breathing is present when attempting to lie flat. Also, code if the resident avoids lying flat because of shortness of breath.
      • Respiratory therapy can be coded in O0400D when a respiratory therapist or respiratory nurse documents at least 15 minutes per day with time including evaluation/assessment, treatment administration and monitoring, and setup and removal of treatment equipment.
      • Skin conditions (ulcers, wounds, or lesions) should be documented appropriately including the description, location and etiology.
      • Monitor nurse’s notes, vital reports, etc. for residents with fever which includes a temperature of 100.4 degrees on admission or 2.4 degrees F higher than baseline. Routinely establish a baseline temperature shortly after admission and update with annual assessment.
      • Restorative nursing programs can be captured when requirements are met. Review this documentation during the reference period to ensure at least 15 minutes per day with two programs is delivered by trained staff.  Also, ensure that nurse supervision and evaluation are present.
      • Behavioral symptoms such as physical, verbal, wandering, rejection of care or other behaviors documented in the 7-day reference period should include actual examples. Document these behaviors even if “normal” for the resident.
      • Impaired cognition determined by BIMS, or Cognitive Performance Scale must be completed and signed in Z0400 during the look-back period.

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Kristen Walden, MSN, RN, RAC-CT Clinical Consultant

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