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ICD-10-CM 2027 diagnosis code

I28.9Disease of pulmonary vessels, unspecified

✓ Billable / specific

I28.9 is a valid, billable ICD-10-CM code for disease of pulmonary vessels, unspecified. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About I28.9

I28.9 is the ICD-10-CM diagnosis code for disease of pulmonary vessels, unspecified. It belongs to category I28 (other diseases of pulmonary vessels), 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 I28, choose I28.9 (Disease of pulmonary vessels, unspecified) only when documentation doesn't support a more specific option: arteriovenous fistula of pulmonary vessels (I28.0), aneurysm of pulmonary artery (I28.1) and other diseases of pulmonary vessels (I28.8).

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 has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 417.9 (unspecified disease of pulmonary circulation).

Notes that apply from higher levels

Instructions written at a parent level also apply to I28.9.

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 I28.9.

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.

ICD-9-CM equivalent

Converter →
  • 417.9Unspecified disease of pulmonary circulationexact

From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.

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
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about I28.9

Is I28.9 billable?

Yes. I28.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can I28.9 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict I28.9 as a principal diagnosis.

Is I28.9 a CC or MCC?

No. I28.9 is neither a CC nor an MCC under MS-DRG v44.0.

What DRG does I28.9 group to?

I28.9 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.

What is the ICD-9 code for I28.9?

The CMS General Equivalence Mappings map I28.9 to ICD-9-CM 417.9.