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[Blog Series] Transition to PDPM Part 1: Cost of Errors Related to Diagnosis Coding and Section GG

December 12, 2019
Documentation, Billing, & Coding By Kay Hashagen, Senior Consultant

Welcome to the world of the Patient Driven Payment Model (PDPM)! Since October 1, 2019, anyone who is participating in the Skilled Nursing Facility (SNF) arena and treating patients with Medicare Part A must know that this monumental change in reimbursement took place. Everyone has been anxiously waiting to see the impact. Clients are asking “Are there any national averages for PDPM components yet?” and wondering how the PDPM rates will compare with historical RUGs rates. It is too early to really know, and remember, October 2019 reimbursement will be skewed due to the many Interim Payment Assessments (IPA) that were done to convert existing patients to PDPM. November 2019 will be the first typical month under PDPM.


Transition _to_PDPM_Part_1_graphic-1

At LW Consulting, Inc. (LWCI), we have been busy assisting clients with PDPM audits to identify whether the PDPM Health Insurance Prospective Payment System (HIPPS) code billed on the Minimum Data Set (MDS) and the UB-04 is supported by the documentation. In this 3-part PDPM blog series, we will highlight errors we have been seeing related to diagnosis coding and Section GG. 

Let’s begin with a brief overview of the clinical metrics for Physical Therapy (PT) and Occupational Therapy (OT) that relate to the PDPM components. The two drivers of the PT and OT components are the coding of the primary medical diagnosis and Section GG information. Primary medical diagnosis coding will be located in the MDS Section I0020B. The code entered in the MDS in Section I0020B supports the patient characteristics for the reason for the SNF admission. Physician documentation is required to support the code and the therapy medical diagnosis and evaluations should also support this code. Section GG information is recorded in the MDS Section GG. Per the definition and instructions in the Long-Term Care (LTC) Facility Resident Assessment Instrument (RAI) Manual, Chapter 3, Section GG, documentation supporting the patient’s usual performance over the first three days of admission (for 5-Day MDS) should be what is coded. For an IPA, the usual performance for the Assessment Reference Date (ARD) and the preceding two days is where the Section GG information should come from. Both nursing and therapy documentation should be reviewed to support Section GG coding on the MDS.

When reviewing documentation to support PDPM coding the 5-digit HIPPS code that is on the UB-04 must be deciphered. Here is the outline of what each of the characters in the HIPPS code refer to:

  • Character 1: PT/OT Payment Group
  • Character 2: Speech-Language Pathology (SLP) Payment Group
  • Character 3: Nursing Payment Group
  • Character 4: Non-Therapy Ancillary (NTA) Payment Group and
  • Character 5: Assessment Indicator.

The first character relates to both the PT and OT components, even though the reimbursement for each of the two is slightly different. The characters all start with the letter “T”, which may mean “Therapy.” The alphabet, from A through P, is then used to identify payment group codes for PT and OT.  Within the PT and OT categories, the Centers for Medicare and Medicaid Services (CMS) has outlined four primary diagnosis categories. Within each of the four categories are four levels of payment related to Section GG Function Scores. The primary diagnosis clinical categories are Major Joint Replacement or Spinal Surgery, Other Orthopedic, Medical Management, Non-Orthopedic Surgery and Acute Neurologic. The function scores for PT and OT are 0-5 points, 6-9 points, 10-23 points and 24 points. The clinical category and the function score match to form a PT/OT Case-Mix Group which correlates to a PT Case Mix Index (CMI) and an OT CMI. These are then related to either urban or rural PT and OT rates. 

Summary of Findings Related to Recent Audits for Diagnosis Coding

  • The prevalence of Return to Provider (RTP) codes in I0020B has been very limited. This is to be commended because coding an RTP code in I0020B would cause reimbursement to be provider liable for the entire stay, or until an IPA could be performed. Best practice is for a designated person to verify that the primary diagnosis code and reason for the SNF admission is not on the CMS list of diagnoses as a RTP code. For more information, review the PDPM ICD-10 Mappings under the PDPM Resources.
  • When there is more than one possible diagnosis code, that could be utilized as the primary diagnosis code, most facilities are choosing the one that is supported by the highest reimbursement. This is a supportable recommendation as long at the physician documentation supports the coding choice.
  • In order to choose a code as the primary diagnosis, the requirements in the RAI Manual 3.0, Chapter 3, Section I must be followed. These include a physician documented diagnosis within the past 60 days and documentation to then support that the diagnosis is active within the last 7 days of the ARD [except if the RAI Manual has other timeframes which are listed, i.e. UTI has a 30 day look back). It is important to verify that the physician documentation supports these criteria. There are times when the auditors identify documentation that has not been signed by the physician, and this documentation cannot be utilized to support the coding.
  • LWCI auditors find that additional documentation to support a better code may be embedded in hospital discharge information. Utilization of hospital discharge information may mean review of the best date for the ARD to be able to capture the hospital information in the 7-day look back period. This requires the Interdisciplinary Team (IDT) to discuss and plan the ARD for assessments.

Summary of Findings Related to Recent Audits for Section GG Coding

  • When coding Section GG, remember to include data from only the first three days of admission for the 5-day assessment and the ARD and two preceding days for an IPA. We have identified coding on the MDS that utilizes the entire 7-day lookback (which is the allowable rule for Section G review not GG). Section GG coding that is not supported causes an invalid PDPM HIPPS code.
  • We are continuing to identify that the coding choices for Section GG are not the “usual performance” but relate to the “most dependent” requirement for assistance. This is a reversion to the Section G rules. Monitor to ensure that all coding supports “usual performance” during the appropriate lookback period.
  • If the facility is utilizing only therapy documentation or only nursing documentation for the MDS coding, often auditors identify choices that change the Section GG coding. When this happens, both the first HIPPS character for the PT/OT component and the third character for the Nursing component will change. This changes reimbursement and may cause an “overpayment” scenario.
  • Often auditors cannot locate documentation to support the coding on the MDS for the specific Section GG tasks. If the MDS Coordinator is coding based on general statements, these do not meet the RAI definitions, and CMS may not allow them. For example: if nursing and therapy document “transfers moderate assistance” and that is used to code “sit to stand” and “bed to chair/wheelchair transfers,” this information is not specific enough. Any missing documentation causes an “INVALID PDPM” HIPPS code to be calculated in the CMS grouper. This could be construed as a provider liable payment situation.

Example of Financial Impact From an Audit

MDS Findings

The Section GG coding on the MDS equals 10 points, supporting the “G” HIPPS modifier for PT/OT.  The audited Section GG for eating was scored at a “4,” instead of the billed “5.” This changed the total Section GG to only 9 points, supporting the change in the PT/OT component from “G” to “F.”

Financial Impact

For all days, the daily rate changes from $521.64 to $515.73 per day due to this one coding error. This is an overpayment of $5.32 per day. If the patient had a 20 day stay, that would equal $106.40 that might have to be returned to CMS for that one coding error on eating.

In summary, the devil is in the detail for PDPM. Documentation to support the coding on the MDS for diagnosis and Section GG must be specific, timely and accurate. In most audits, LWCI is identifying coding errors not supported by documentation that lead to reimbursement for PDPM being higher than what the documentation supports. Now is the time to identify root causes of documentation and coding errors before CMS starts looking and requesting repayment for “overpayments.”


For more information on our PDPM support packages to assist you with audits, training, systems and coaching, contact Kay Hashagen at 410-777-5999 or email

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