FY 2027 IPF PPS (CR 14591): corrected $912.13 per diem and 38 ICD-10-CM comorbidity code adds

On October 8, 2026, CMS issued Transmittal R14000CP, Change Request 14591, the FY 2027 update to the Inpatient Psychiatric Facility Prospective Payment System (IPF PPS). It applies to discharges from October 1, 2026 through September 30, 2027, with an implementation date of October 5, 2026. CMS released MM14591, the MLN Matters article, the same day.

R14000CP rescinds and replaces Transmittal 13920, issued September 11, 2026. CMS says the reissue clarifies how an IPF's FTE resident cap is calculated when slots were awarded under section 4122 of the Consolidated Appropriations Act, 2023, and that "All other information remains the same."

Two things matter for IPF billing and coding desks. First, the rate figures in the CR and the MLN article do not match. Second, the FY 2027 comorbidity code lists changed, and the final rule printed one of those counts wrong.

CR 14591 at a glance

$912.13, not $912.40: which FY 2027 IPF rate is right

The FY 2027 IPF PPS final rule (91 FR 48514, July 31, 2026) set the federal per diem base rate at $912.40. On October 1, 2026, CMS published a correction notice (CMS-1847-CN). CMS had treated one IPPS hospital, CCN 250078, as if it had converted to a rural emergency hospital, which left its data out of the wage index. Restoring that data changed the wage index for CBSA 25620 (Hattiesburg, Mississippi). It also moved the wage index budget neutrality factor from 0.9989 to 0.9986, and that factor feeds every FY 2027 IPF rate.

The MLN article's figures are the final rule's pre-correction numbers. The CR, the FY 2027 Addendum A (marked updated 10/01/2026), and the Federal Register correction all show the corrected figures. Business requirement 14591.3 tells CMS to make sure the IPF PPS Pricer includes all FY 2027 updates. If your claim scrubber, contract model, or expected-payment table was built from the MLN article, recheck it against the CR and Addendum A.

The figures both documents agree on:

• Fixed dollar loss threshold: $40,750
• Labor-related share 78.9 percent; non-labor-related share 21.1 percent
• Adjusted market basket update of 2.3 percent (3.2 percent market basket less a 0.9 percentage point productivity adjustment), applied to the FY 2026 base rate of $892.87
• An update of 0.3 percent for IPFs that failed IPF Quality Reporting Program requirements
• An 18 percent rural adjustment, with no rural adjustment for IPFs that became urban in FY 2025 under the revised CBSA delineations

The correction also fixes the final rule's text on the Day 1 variable per diem adjustment for IPFs without a qualifying emergency department: 1.27 becomes 1.28. Addendum A and the CR attachment both list 1.28 for Day 1 without a qualifying ED and 1.54 with one.

38 ICD-10-CM codes join the FY 2027 IPF comorbidity lists

IPF comorbidity adjustments pay more for certain secondary conditions. The final rule describes the rules this way: comorbid conditions "must exist at the time of admission or develop subsequently, and affect the treatment received, length of stay (LOS), or both treatment and LOS." An IPF "may receive only one comorbidity adjustment within a comorbidity category, but it may receive an adjustment for more than one comorbidity category," and claims carry up to 24 additional diagnoses. CMS retained the existing comorbidity adjustment factors for FY 2027.

The FY 2027 Addendum B summary of changes lists these additions. CMS prints the codes without the decimal; they are shown here in standard ICD-10-CM format.

Each Poisoning group covers the four intents CMS lists (accidental, intentional self-harm, assault, undetermined), and every added Poisoning code is an initial encounter (A) code. The cardiac additions include dilated cardiomyopathy (I42.00, I42.01, I42.09), arrhythmogenic cardiomyopathy (I42.81), catecholaminergic polymorphic ventricular tachycardia (I47.22), Brugada syndrome (I49.81), and ventricular bigeminy (I49.82). The oncology additions are secondary malignant neoplasm of the larynx, pharynx, and oral cavity.

Removals: M86.8X- osteomyelitis and T52.8X- solvents

Addendum B also removes codes:

Check the FY 2027 ICD-10-CM code set for context. In our checks against that set, M86.8X1 through M86.8X8 are now category headers that are not valid on a claim, and T52.8X1A and T52.8X4S were retired after FY 2026. On the solvent side, Addendum B adds the initial encounter codes listed above from T52.81-, T52.82-, and T52.89- to the Poisoning list. Code FY 2027 discharges to a complete, valid FY 2027 code, not a header.

The "10" that should have read "20"

The final rule says CMS is "adding 10 ICD-10-CM diagnosis codes to the Poisoning code list." The October 1 correction notice fixes that figure: "the figure '10' is corrected to read '20'." Addendum B lists 20 Poisoning codes, so the list itself was right; only the preamble count was wrong. If your team built an FY 2027 IPF change log from the final rule text, update that count.

What did not change for FY 2027

• ECT procedure codes: R14000CP says "There were no changes for FY 2027 to the IPF ECT procedure code list."
• Comorbidity adjustment factors: retained from the FY 2025 revision.
• IPF MS-DRG adjustments: CMS kept payment adjustments for psychiatric diagnoses that group to the existing 19 IPF MS-DRGs. The diagnoses behind those MS-DRGs follow the FY 2027 IPPS ICD-10-CM/PCS code sets, which are on the IPPS tables page.
• Code first logic: the final rule restates that when the psychiatric diagnosis carries a code first note, you follow the ICD-10-CM Tabular List and sequence the underlying condition first. The GROUPER then treats the principal diagnosis as non-psychiatric and searches the secondary diagnoses for the psychiatric code used for the MS-DRG adjustment.

What this is not

It is not a CMS-HCC, V28, or risk adjustment model change. IPF comorbidity categories are IPF PPS payment adjusters, and adding a code to one does not assign or change an HCC.

It is not the acute care IPPS update, and it is not an NCCI update.

For ICD-10-CM wording on any of the codes above, look them up in the encoder or code book. For IPF comorbidity category membership, code first entries, and ECT procedure codes, use the CMS IPF PPS files (Addendum A and Addenda B through B-4) and your MAC's Pricer, not a copied list.