ICD-10-CM 2027 diagnosis code
J4BPulmonary mycetoma
J4B is a valid, billable ICD-10-CM code for pulmonary mycetoma. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.
Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS, effective October 1, 2026. Updated September 29, 2026. About our data
About J4B
J4B is the ICD-10-CM diagnosis code for pulmonary mycetoma. It belongs to block J40-J4B (chronic lower respiratory diseases) 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.
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), DRG 793 (Full Term Neonate with Major Problems, relative weight 4.2195), DRG 974 (HIV with Major Related Condition with MCC, relative weight 3.0506) and 2 more, in MDC 04 (Diseases and Disorders of the Respiratory System), MDC 15 (Newborns and Other Neonates with Conditions Originating in the Perinatal Period) and MDC 25 (Human Immunodeficiency Virus Infections), 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 FY2027, effective October 1, 2026.
Coding notes
Notes that apply from higher levels
Instructions written at a parent level also apply to J4B.
Broader instructions also apply from J40-J4B Chronic lower respiratory diseases and Chapter 10: Diseases of the respiratory system.
Alphabetic index entries
2 entriesTerms in the official ICD-10-CM index that lead to J4B.
Codes whose notes reference J4B
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 04 · Diseases and Disorders of the Respiratory System
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 25 · Human Immunodeficiency Virus Infections
Code history
- 2016
- 2017
- 2018
- 2019
- 2020
- 2021
- 2022
- 2023
- 2024
- 2025
- 2026
- 2027
- FY2027 (effective 10/1/2026): Added
Common questions about J4B
Is J4B billable?
- Yes. J4B is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can J4B be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict J4B as a principal diagnosis.
Is J4B a CC or MCC?
- J4B is an MCC (major complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.
What DRG does J4B group to?
- J4B 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), MS-DRG 793 (Full Term Neonate with Major Problems), MS-DRG 974 (HIV with Major Related Condition with MCC) and 2 more. Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.
Did J4B change for 2027?
- Yes. For FY2027 (effective October 1, 2026) it was added to the code set.