2027 ICD-10-CM Diagnosis Code J4BPulmonary mycetoma
ICD-10-CM Codes›J00–J99›J40-J4B›J4B
- Billable — Valid for Submission
- MCC — Major Complication or Comorbidity
- New 2027 Code
J4B is a billable ICD-10-CM diagnosis code for pulmonary mycetoma. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 177 through 179, 791, 793, 974 through 976. As a secondary diagnosis, it counts as a major complication or comorbidity (MCC) and places an inpatient stay in the highest severity level of its MS-DRG family. It does not count, however, when the principal diagnosis is one of 24 closely related codes.
Code Identity
Code Classification
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to J4B: its own notes plus those printed at block J40-J4B and Chapter 10. A note printed at a category, block or chapter applies to every code under it.
Applicable To
Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.
- Pulmonary fungal ball
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
- bronchitis due to chemicals, gases, fumes and vapors (J68.0)
Excludes2
Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.
- cystic fibrosis (E84.-)
- certain conditions originating in the perinatal period (P04-P96)
- certain infectious and parasitic diseases (A00-B99)
- complications of pregnancy, childbirth and the puerperium (O00-O9A)
- congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
- endocrine, nutritional and metabolic diseases (E00-E88)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- smoke inhalation (T59.81-)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
Code Also
A second code may be needed to fully describe the condition; the note gives no sequencing direction.
Notes
General instructions on how these codes are used.
- When a respiratory condition is described as occurring in more than one site and is not specifically indexed, it should be classified to the lower anatomic site (e.g. tracheobronchitis to bronchitis in J40).
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name J4B, its category, or a range that includes it.
Excludes2 1
These codes carry an Excludes2 note naming J4B: its condition is not part of those codes, and both may be reported when the patient has both.
- B47 Mycetomapulmonary mycetoma (J4B)
Code Also 7
These codes say J4B may also be needed to fully describe the condition. The note gives no sequencing direction.
- B37.1 Pulmonary candidiasispulmonary mycetoma (J4B)
- B38.0 Acute pulmonary coccidioidomycosispulmonary mycetoma (J4B)
- B38.1 Chronic pulmonary coccidioidomycosispulmonary mycetoma (J4B)
- B38.2 Pulmonary coccidioidomycosis, unspecifiedpulmonary mycetoma (J4B)
- B44 Aspergillosispulmonary aspergilloma (J4B)
- B44 Aspergillosispulmonary aspergillosis fungal ball (J4B)
- B44 Aspergillosispulmonary mycetoma (J4B)
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Code History & ChangesHistory
New Code J4B was added to the ICD-10-CM code set for FY 2027, effective October 1, 2026.
Replacement J4B replaces the following previously assigned code(s):
- B37.1 - Pulmonary candidiasis
- B38.0 - Acute pulmonary coccidioidomycosis
- B38.1 - Chronic pulmonary coccidioidomycosis
- B38.2 - Pulmonary coccidioidomycosis, unspecified
- B44.1 - Other pulmonary aspergillosis
- B47 - Mycetoma
- B47.0 - Eumycetoma
- B47.1 - Actinomycetoma
- B47.9 - Mycetoma, unspecified
- J98.8 - Other specified respiratory disorders
Questions About J4BOverview
What is the ICD-10 code for pulmonary mycetoma?
The ICD-10-CM code for pulmonary mycetoma is J4B. It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is J4B (Pulmonary mycetoma) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report pulmonary mycetoma on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does J4B group to?
When pulmonary mycetoma is the principal diagnosis on an inpatient stay, it groups to MS-DRG 793, 791, 974, 976, 975, 179, 178, 177, with relative weights from 0.7344 to 4.2192 depending on complications. Higher weights mean higher Medicare reimbursement.
Is J4B a CC or MCC?
CMS lists J4B as an MCC (major complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it places the inpatient stay in the highest-weighted DRG of its severity family. It does not count when the principal diagnosis is one of the 24 closely related codes in its exclusion list.
Can J4B be reported with J68.0?
Not as a rule. The Excludes1 note at block J40-J4B, which applies to J4B, lists "bronchitis due to chemicals, gases, fumes and vapors (J68.0)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).
