ICD-10-CM 2027
ICD-10 code for diphtheritic cystitis
From the official ICD-10-CM alphabetic index entry “Cystitis (exudative) (hemorrhagic) (septic) (suppurative) › diphtheritic”. Page updated September 29, 2026.
About coding diphtheritic cystitis
The ICD-10-CM code for diphtheritic cystitis is A36.85 (Diphtheritic cystitis).
Within A36.8 (other diphtheria), A36.85 is specifically for diphtheritic cystitis. Related codes cover diphtheritic cardiomyopathy (A36.81), diphtheritic radiculomyelitis (A36.82), diphtheritic polyneuritis (A36.83), diphtheritic tubulo-interstitial nephropathy (A36.84), diphtheritic conjunctivitis (A36.86) and other diphtheritic complications (A36.89).
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 689 (Kidney and Urinary Tract Infections with MCC, relative weight 1.1415) and DRG 690 (Kidney and Urinary Tract Infections without MCC, relative weight 0.801), in MDC 11 (Diseases and Disorders of the Kidney and Urinary Tract), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
Common questions about diphtheritic cystitis ICD-10 codes
What is the ICD-10 code for diphtheritic cystitis?
- A36.85 — Diphtheritic cystitis.
Is A36.85 billable?
- Yes. A36.85 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can A36.85 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict A36.85 as a principal diagnosis.
Is A36.85 a CC or MCC?
- A36.85 is a CC (complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.