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ICD-10-CM 2027 diagnosis code

S25.409AUnspecified injury of unspecified pulmonary blood vessels, initial encounter

✓ Billable / specificRequires 7th characterMCC — major complication/comorbidityUnspecified — edit

S25.409A is a valid, billable ICD-10-CM code for unspecified injury of unspecified pulmonary blood vessels, initial encounter. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.Short description: Unsp injury of unsp pulmonary blood vessels, init encntr

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 S25.409A

S25.409A is the ICD-10-CM diagnosis code for unspecified injury of unspecified pulmonary blood vessels, initial encounter. It belongs to category S25 (injury of blood vessels of thorax), block S20-S29 (injuries to the thorax) and chapter 19 (injury, poisoning and certain other consequences of external causes). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

The 7th character "A" means initial encounter: use it while the patient is receiving active treatment for the condition.

As a secondary diagnosis it is an MCC (major complication or comorbidity), which can move an inpatient stay into the highest-paying "with MCC" MS-DRG of its family, unless the principal diagnosis excludes it.

In MS-DRG v44.0, it is part of the grouping logic for DRG 791 (Prematurity with Major Problems, relative weight 4.1075), DRG 793 (Full Term Neonate with Major Problems, relative weight 4.2195), DRG 913 (Traumatic Injury with MCC, relative weight 1.5455), DRG 914 (Traumatic Injury without MCC, relative weight 0.9285), DRG 963 (Other Multiple Significant Trauma with MCC, relative weight 2.6363), DRG 964 (Other Multiple Significant Trauma with CC, relative weight 1.4972) and 1 more, in MDC 15 (Newborns and Other Neonates with Conditions Originating in the Perinatal Period), MDC 21 (Injuries, Poisonings and Toxic Effects of Drugs) and MDC 24 (Multiple Significant Trauma), 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 is an unspecified code for which a more specific option (often laterality) exists, and the Medicare Code Editor flags it for review on inpatient claims.

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 901.40 (injury to pulmonary vessel(s), unspecified), 901.41 (injury to pulmonary artery) and 901.42 (injury to pulmonary vein).

7th character

Ainitial encounter

CC/MCC status for this injury by encounter: MCC for A; Neither CC nor MCC for D, S.

Other encounter types for S25.409:

Notes that apply from higher levels

Instructions written at a parent level also apply to S25.409A.

› From S25 Injury of blood vessels of thorax
Code also
  • any associated open wound (S21.-)

Broader instructions also apply from S20-S29 Injuries to the thorax and Chapter 19: Injury, poisoning and certain other consequences of external causes.

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.

MDC 15 · Newborns and Other Neonates with Conditions Originating in the Perinatal Period

MDC 15 · Newborns and Other Neonates with Conditions Originating in the Perinatal Period

MDC 21 · Injuries, Poisonings and Toxic Effects of Drugs

ICD-9-CM equivalent

Converter →
  • 901.40Injury to pulmonary vessel(s), unspecifiedapproximate
  • 901.41Injury to pulmonary arteryapproximate
  • 901.42Injury to pulmonary veinapproximate

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 S25.409A

Is S25.409A billable?

Yes. S25.409A is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

What does the "A" at the end of S25.409A mean?

It is the 7th character for initial encounter. Per the official guidelines, use it while the patient is receiving active treatment for the condition.

Can S25.409A be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict S25.409A as a principal diagnosis.

Is S25.409A a CC or MCC?

S25.409A is an MCC (major complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.

What DRG does S25.409A group to?

S25.409A is used in the MS-DRG v44.0 logic for MS-DRG 791 (Prematurity with Major Problems), MS-DRG 793 (Full Term Neonate with Major Problems), MS-DRG 913 (Traumatic Injury with MCC), MS-DRG 914 (Traumatic Injury without MCC), MS-DRG 963 (Other Multiple Significant Trauma with MCC), MS-DRG 964 (Other Multiple Significant Trauma with CC) and 1 more. 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 S25.409A?

The CMS General Equivalence Mappings map S25.409A to ICD-9-CM 901.40, 901.41 and 901.42.