ICD-10-CM 2027
ICD-10 code for Zygomycosis
From the official ICD-10-CM alphabetic index entry “Zygomycosis”. Page updated September 29, 2026.
About coding Zygomycosis
The ICD-10-CM code for Zygomycosis is B46.9 (Zygomycosis, unspecified). The official index lists 1 more specific code, so check the documentation for details such as type, cause, site or severity before settling on B46.9.
Within B46, choose B46.9 (unspecified) only when documentation doesn't support a more specific option: pulmonary mucormycosis (B46.0), Rhinocerebral mucormycosis (B46.1), gastrointestinal mucormycosis (B46.2), cutaneous mucormycosis (B46.3), disseminated mucormycosis (B46.4), mucormycosis, unspecified (B46.5) and other zygomycoses (B46.8).
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 867 (Other Infectious and Parasitic Diseases Diagnoses with MCC, relative weight 2.1859), DRG 868 (Other Infectious and Parasitic Diseases Diagnoses with CC, relative weight 1.0235) and DRG 869 (Other Infectious and Parasitic Diseases Diagnoses without CC/MCC, relative weight 0.6787), in MDC 15 (Newborns and Other Neonates with Conditions Originating in the Perinatal Period) and MDC 18 (Infectious and Parasitic Diseases, Systemic or Unspecified Sites), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
More specific Zygomycosis codes (official index)
- specified NEC B46.8 — Other zygomycoses
Common questions about Zygomycosis ICD-10 codes
What is the ICD-10 code for Zygomycosis?
- B46.9 — Zygomycosis, unspecified. More specific codes apply when the documentation supports them: B46.8.
Is B46.9 billable?
- Yes. B46.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can B46.9 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict B46.9 as a principal diagnosis.
Is B46.9 a CC or MCC?
- B46.9 is an MCC (major complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.