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ICD-10-CM 2027 diagnosis code

I27.849Fontan related circulation, unspecified

✓ Billable / specific

I27.849 is a valid, billable ICD-10-CM code for fontan related circulation, unspecified. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.

Looking up by condition? See ICD-10 code for Fontan related circulation.

Code last changed in FY2026 (effective October 1, 2025). Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About I27.849

I27.849 is the ICD-10-CM diagnosis code for Fontan related circulation, unspecified. It belongs to category I27 (other pulmonary heart diseases), block I26-I28 (pulmonary heart disease and diseases of pulmonary circulation) and chapter 9 (diseases of the circulatory system). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within I27.84, choose I27.849 (unspecified) only when documentation doesn't support a more specific option: Fontan-associated liver disease [FALD] (I27.840), Fontan-associated lymphatic dysfunction (I27.841) and other Fontan-associated condition (I27.848).

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

In MS-DRG v44.0, it is part of the grouping logic for DRG 314 (Other Circulatory System Diagnoses with MCC, relative weight 2.0873), DRG 315 (Other Circulatory System Diagnoses with CC, relative weight 0.9508) and DRG 316 (Other Circulatory System Diagnoses without CC/MCC, relative weight 0.6677), in MDC 05 (Diseases and Disorders of the Circulatory System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It was added in FY2026, effective October 1, 2025.

Notes that apply from higher levels

Instructions written at a parent level also apply to I27.849.

Broader instructions also apply from Chapter 9: Diseases of the circulatory system.

Alphabetic index entries

1 entries

Terms in the official ICD-10-CM index that lead to I27.849.

MS-DRG v44.0 grouping

All DRGs →

Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2026 (effective 10/1/2025): Added
  • No changes since FY2026.

Common questions about I27.849

Is I27.849 billable?

Yes. I27.849 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can I27.849 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict I27.849 as a principal diagnosis.

Is I27.849 a CC or MCC?

No. I27.849 is neither a CC nor an MCC under MS-DRG v44.0.

What DRG does I27.849 group to?

I27.849 is used in the MS-DRG v44.0 logic for MS-DRG 314 (Other Circulatory System Diagnoses with MCC), MS-DRG 315 (Other Circulatory System Diagnoses with CC) and MS-DRG 316 (Other Circulatory System Diagnoses without CC/MCC). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.