Medicare Prospective Payment System Under PDPM: The Five Components That Determine Your SNF Reimbursement Rate

The Medicare Prospective Payment System for skilled nursing facilities has undergone one fundamental transformation since its introduction the replacement of the Resource Utilization Groups model (RUG-IV) with the Patient-Driven Payment Model (PDPM) in October 2019. That transition changed not just how Medicare calculates SNF reimbursement, but what it measures, what it rewards, and where the revenue risk in billing accuracy sits.

Under RUG-IV, reimbursement was driven primarily by therapy volume the more minutes of therapy a resident received, the higher the facility’s daily rate. Under PDPM, therapy volume is irrelevant to payment. What determines your daily Medicare reimbursement rate is the clinical complexity of each individual resident, measured across five separate case-mix components derived from MDS assessment data.

Understanding how each component works what drives it, what the most common coding gaps are, and what the financial consequence of under coding looks like is the starting point for protecting the Medicare reimbursement accuracy your facility depends on.

How the Medicare Prospective Payment System Calculates Your Daily Rate Under PDPM?

Under PDPM, Medicare pays skilled nursing facilities a daily per-diem rate for each day of a covered Part A stay. That rate is not fixed it is calculated separately for each resident based on their individual PDPM classification across the five case-mix components. The five component rates are added together to produce the total daily payment for that resident.

The classification is encoded in a five-character alphanumeric code called the HIPPS code Health Insurance Prospective Payment System code that appears on every Medicare Part A SNF claim. The HIPPS code is generated algorithmically from MDS assessment data. Each character in the HIPPS code encodes one component’s classification. The accuracy of the HIPPS code is entirely dependent on the accuracy of the MDS assessment that generates it.

What this means for your facility: Your daily Medicare reimbursement rate is not a number your billing team enters it is a number the system calculates from your MDS data. If the MDS data is inaccurate, the reimbursement rate is inaccurate. And because the same HIPPS code applies to every day of the covered stay until a new assessment is completed, a single MDS coding error affects days or weeks of payment.

Component 1: Physical Therapy

The Physical Therapy component is determined by two factors: the resident’s primary diagnosis and their functional score. The primary diagnosis must map to one of the clinical categories on CMS’s PDPM ICD-10 mapping table specific diagnostic groupings that each carry a PT classification tier. CMS updates this mapping table annually, and primary diagnosis codes that are not on the table, or that map to the non-case-mix (non-CC) category, generate the lowest possible PT component rate.

The functional score derived from Section GG of the MDS, which assesses the resident’s ability to perform specific self-care and mobility activities determines which of three functional impairment tiers the resident falls into: low, medium, or high. Higher functional impairment generates a higher PT component rate. Section GG items that are scored generically rather than through direct clinical observation, or that reflect an optimistic average rather than the resident’s actual performance at assessment, frequently place residents in lower functional impairment tiers than their condition warrants.

What this means for your facility: Two specific coding decisions determine the PT component rate: primary diagnosis code selection and Section GG scoring. A primary diagnosis code that maps to a lower clinical category than the clinical record supports reduce the PT rate for the entire stay. A Section GG score that does not accurately reflect actual functional impairment reduces both the PT and OT component rates simultaneously.

Component 2: Occupational Therapy

The Occupational Therapy component is calculated using the same primary diagnosis mapping and Section GG functional score as the PT component, but its payment rates are calculated independently. This means a coding error that affects the PT and OT clinical category simultaneously reduces two component rates, not one.

The OT component also applies variable rate adjustments based on whether the resident is in the early period (days one through sixty of a continuous Part A stay) or the late period (day sixty-one and beyond). Early period rates are higher than late period rates, reflecting CMS’s assumption that care intensity is typically greater in the early portion of a post-acute SNF stay. Accurate tracking of continuous enrolment days to ensure the correct early or late period rate is applied is a billing function that requires active management in facilities with long-stay Medicare Part A residents.

Component 3: Speech-Language Pathology

The Speech-Language Pathology component is driven by a combination of cognitive status, swallowing disorders, and specific SLP-relevant diagnoses. The Brief Interview for Mental Status (BIMS) score from Section C of the MDS, which measures cognitive function, directly affects the SLP component rate residents with cognitive impairment receive higher SLP component payment than those without.

Swallowing disorder documentation is one of the most consistently under coded SLP drivers. A resident who requires a mechanically altered diet, thickened liquids, or who has documented dysphagia carries a higher SLP component rate but only when the swallowing disorder is specifically coded in the MDS and supported by clinical documentation that establishes the skilled care need. Similarly, specific SLP diagnoses including aphasia, laryngectomy, and motor speech disorders each carry higher SLP component classifications that are frequently missed when primary diagnoses focus on the reason for the SNF admission rather than the full clinical picture.

What this means for your facility: The SLP component is frequently the most under coded therapy component in SNF billing because its driver’s cognitive status, swallowing disorders, and specific neurological diagnoses are less directly connected to the post-acute admission reason than PT and OT drivers. A systematic SLP component review against the clinical record, specifically for swallowing disorder documentation and qualifying diagnoses, consistently identifies payment that was available but not captured.

Component 4: Nursing

The Nursing component is the largest single payment component for most long-stay SNF residents and the most consistently under coded. It is driven by a combination of clinical conditions and nursing-intensive care needs documented across multiple MDS sections, primarily Section I (active diagnoses) and Section O (special treatments and programs).

The clinical conditions that drive the Nursing component include active infections such as septicaemia, pneumonia, and urinary tract infections with specific comorbidity designations, IV medications and infusions, tracheostomy care, ventilator or respiratory therapy dependence, wounds requiring skilled nursing management, depression diagnosis with active treatment, and a range of other conditions that increase nursing care intensity. Each qualifying condition carries a specific Nursing component classification tier and each condition that is present in the clinical record but absent from the MDS produces a lower Nursing component rate.

The Nursing component is under coded most frequently for two reasons. First, the conditions that drive it infections, IV medications, depression require nursing documentation specificity that the prior therapy-volume model never incentivized, so long-tenured nursing teams may not have the documentation habits the PDPM model rewards. Second, the MDS coordinator completing the assessment may not have a systematic process for cross-referencing the clinical record against the Nursing component trigger list before the assessment is locked.

What this means for your facility: Of all five PDPM components, the Nursing component represents the largest revenue opportunity for facilities that have not audited their MDS coding since PDPM launched. A systematic review that validates Nursing component triggers against clinical documentation specifically for infections, IV medications, and comorbid conditions routinely identifies significant daily rate gaps that compound across every Part A Day in the affected resident population.

Component 5: Non-Therapy Ancillaries

The Non-Therapy Ancillary component captures the cost of medications, laboratory services, medical supplies, and other ancillary services that are not attributable to therapy. It is calculated from an NTA score a point-based system that assigns specific values to comorbid conditions and medications documented in the MDS.

High-cost medications carry the highest NTA point values and include parenteral nutrition, IV antibiotics, chemotherapy agents, dialysis, and certain specialty drugs. Comorbid conditions including multiple sclerosis, end-stage renal disease, severe skin ulcers, and several others each carry NTA point values that reflect their resource intensity. The NTA score is the sum of all qualifying point values for a resident and the NTA component rate increases with higher cumulative scores.

The NTA component is consistently under coded for the same reason as the Nursing component: it requires a systematic review of secondary diagnoses and active medications against a specific list of qualifying conditions and drugs. Facilities that code only the primary diagnosis and the most prominent comorbidities, without a structured secondary diagnosis review against the NTA point table, regularly leave NTA component payment uncaptured.

What this means for your facility: The NTA component is particularly impactful in the first three days of a Medicare Part A stay CMS applies a higher NTA payment rate for days one through three to reflect the front-loaded resource intensity of post-acute admissions. Ensuring that NTA-qualifying conditions and medications are coded accurately on the five-day assessment, which covers those first three days, is a high-priority revenue protection step for every new Medicare admission.

The Revenue Consequence of Getting the Five Components Wrong

Because PDPM calculates a separate component rate for each of the five areas and sums them into a single daily rate, an error in any one component affects every day of the covered stay. An MDS that under codes the Nursing component by one classification tier may reduce the daily rate by fifteen to thirty dollars which translates to $450 to $900 in lost revenue across a 30-day stay, multiplied by every resident with the same under coding pattern.

Across a 100-bed facility with consistent Nursing and NTA under coding, the annual revenue gap from PDPM alone can reach six figures without ever appearing in a denial report. The claims are accepted and paid just paid at the wrong rate. The only way to identify this revenue gap is through a PDPM case-mix audit that compares the HIPPS code distribution against the clinical complexity of the resident population.

How MCA Medical Billing Solutions L.L.C. Protects Your PDPM Reimbursement Accuracy

MCA Medical Billing Solutions, L.L.C. validates PDPM component coding against the clinical record before every MDS assessment is locked specifically reviewing the Nursing and NTA components where under coding is most prevalent, confirming Section GG functional scoring accuracy, and verifying that primary diagnosis codes map correctly to the appropriate PDPM clinical categories.

If your facility has not performed a PDPM case-mix audit since October 2019, the audit itself may be the most valuable billing exercise you have not yet done. Contact MCA for a free billing assessment that includes a PDPM reimbursement accuracy review.