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ICD-10-CM 2027 diagnosis code

J98.51Mediastinitis

✓ Billable / specificMCC — major complication/comorbidity

J98.51 is a valid, billable ICD-10-CM code for mediastinitis. 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 Mediastinitis.

Code last changed in FY2017 (effective October 1, 2016). Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About J98.51

J98.51 is the ICD-10-CM diagnosis code for Mediastinitis. It belongs to category J98 (other respiratory disorders), block J96-J99 (other diseases of the respiratory system) and chapter 10 (diseases of the respiratory 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 J98.5 (diseases of mediastinum, not elsewhere classified), J98.51 is specifically for Mediastinitis. Related codes cover other diseases of mediastinum, not elsewhere classified (J98.59).

Code first: underlying condition, if applicable, such as postoperative mediastinitis (T81.-).

Use an additional code to identify: exposure to environmental tobacco smoke (Z77.22), exposure to tobacco smoke in the perinatal period (P96.81), history of tobacco dependence (Z87.891), occupational exposure to environmental tobacco smoke (Z57.31), tobacco dependence (F17.-) and 1 more.

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 177 (Respiratory Infections and Inflammations with MCC, relative weight 1.6092), DRG 178 (Respiratory Infections and Inflammations with CC, relative weight 0.9744), DRG 179 (Respiratory Infections and Inflammations without CC/MCC, relative weight 0.7345), DRG 791 (Prematurity with Major Problems, relative weight 4.1075) and DRG 793 (Full Term Neonate with Major Problems, relative weight 4.2195), in MDC 04 (Diseases and Disorders of the Respiratory System) and MDC 15 (Newborns and Other Neonates with Conditions Originating in the Perinatal Period), 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 FY2017, effective October 1, 2016.

Before ICD-10, this condition was coded in ICD-9-CM as 519.2 (Mediastinitis).

Coding notes

Code firstSequence the underlying condition first
  • underlying condition, if applicable, such as postoperative mediastinitis (T81.-)

Notes that apply from higher levels

Instructions written at a parent level also apply to J98.51.

› From J98.5 Diseases of mediastinum, not elsewhere classified
Excludes2
  • abscess of mediastinum (J85.3)
› From J98 Other respiratory disorders
Excludes1
Excludes2
Use additional code
  • code to identify:
  • exposure to environmental tobacco smoke (Z77.22)
  • exposure to tobacco smoke in the perinatal period (P96.81)
  • history of tobacco dependence (Z87.891)
  • occupational exposure to environmental tobacco smoke (Z57.31)
  • tobacco dependence (F17.-)
  • tobacco use (Z72.0)

Broader instructions also apply from Chapter 10: Diseases of the respiratory system.

Alphabetic index entries

2 entries

Terms in the official ICD-10-CM index that lead to J98.51.

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

ICD-9-CM equivalent

Converter →

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
  • FY2017 (effective 10/1/2016): Added
  • No changes since FY2017.

Common questions about J98.51

Is J98.51 billable?

Yes. J98.51 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can J98.51 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict J98.51 as a principal diagnosis.

Is J98.51 a CC or MCC?

J98.51 is an MCC (major complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.

What DRG does J98.51 group to?

J98.51 is used in the MS-DRG v44.0 logic for MS-DRG 177 (Respiratory Infections and Inflammations with MCC), MS-DRG 178 (Respiratory Infections and Inflammations with CC), MS-DRG 179 (Respiratory Infections and Inflammations without CC/MCC), MS-DRG 791 (Prematurity with Major Problems) and MS-DRG 793 (Full Term Neonate with Major Problems). 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 J98.51?

The CMS General Equivalence Mappings map J98.51 to ICD-9-CM 519.2.