ICD-10-CM 2027
ICD-10 code for diphtheria
From the official ICD-10-CM alphabetic index entry “Diphtheria, diphtheritic (gangrenous) (hemorrhagic)”. Page updated September 29, 2026.
About coding diphtheria
The ICD-10-CM code for diphtheria is A36.9 (Diphtheria, unspecified). The official index lists 12 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on A36.9.
Within A36, choose A36.9 (unspecified) only when documentation doesn't support a more specific option: pharyngeal diphtheria (A36.0), nasopharyngeal diphtheria (A36.1), laryngeal diphtheria (A36.2), cutaneous diphtheria (A36.3) and other diphtheria (A36.8).
As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" 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 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 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 diphtheria codes (official index)
- carrier (suspected) Z22.2 — Carrier of diphtheria
- cutaneous A36.3 — Cutaneous diphtheria
- faucial A36.0 — Pharyngeal diphtheria
- infection of wound A36.3 — Cutaneous diphtheria
- laryngeal A36.2 — Laryngeal diphtheria
- myocarditis A36.81 — Diphtheritic cardiomyopathy
- nasal, anterior A36.89 — Other diphtheritic complications
- nasopharyngeal A36.1 — Nasopharyngeal diphtheria
- neurological complication A36.89 — Other diphtheritic complications
- pharyngeal A36.0 — Pharyngeal diphtheria
- specified site NEC A36.89 — Other diphtheritic complications
- tonsillar A36.0 — Pharyngeal diphtheria
Common questions about diphtheria ICD-10 codes
What is the ICD-10 code for diphtheria?
- A36.9 — Diphtheria, unspecified. More specific codes apply when the documentation supports them: Z22.2, A36.3, A36.0, A36.3 and others below.
What is the ICD-10 code for carrier diphtheria?
- Z22.2 — Carrier of diphtheria.
What is the ICD-10 code for cutaneous diphtheria?
- A36.3 — Cutaneous diphtheria.
What is the ICD-10 code for faucial diphtheria?
- A36.0 — Pharyngeal diphtheria.
What is the ICD-10 code for infection of wound diphtheria?
- A36.3 — Cutaneous diphtheria.
What is the ICD-10 code for laryngeal diphtheria?
- A36.2 — Laryngeal diphtheria.
What is the ICD-10 code for myocarditis diphtheria?
- A36.81 — Diphtheritic cardiomyopathy.
Is A36.9 billable?
- Yes. A36.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can A36.9 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict A36.9 as a principal diagnosis.
Is A36.9 a CC or MCC?
- A36.9 is a CC (complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.