A36.85 ICD-10-CM Code: Diphtheritic cystitis
HCC Buddy Code Card
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FY 2026 Apr update / Certain infectious and parasitic diseases (A00-B99) / Other bacterial diseases (A30-A49)
A36.85
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceDiphtheritic cystitis
This is an infection of the bladder caused by diphtheria bacteria, which can cause inflammation and damage to the bladder lining. It is a serious complication that occurs when diphtheria spreads to the urinary system.
CMS-HCC V28
N/A—
Not mapped
CMS-HCC V24
N/A—
Not mapped
ACA/HHS
N/A—
Not mapped
ESRD/PACE
N/A—
Not mapped
RXHCC
N/A—
Not mapped
Code Book Path
Inclusion Terms
OfficialICD-10-CM does not list inclusion terms for A36.85 in this effective period.
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for A36.85 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for A36.85 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for A36.85 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for A36.85 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for A36.85 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for A36.85 in this effective period.
Buddy Documentation Tip
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
Is A36.85 an HCC code?
No. A36.85 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
- Code
- A36.85
- Description
- Diphtheritic cystitis
- HCC (V28)
- No CMS-HCC V28 mapping
- RAF
- —
- Billable
- Yes
- Payment year
- 2026
Coder workflow notes
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This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
A36.85 is the ICD-10-CM diagnosis code for diphtheritic cystitis. This is an infection of the bladder caused by diphtheria bacteria, which can cause inflammation and damage to the bladder lining. It is a serious complication that occurs when diphtheria spreads to the urinary system. A36.85 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering other bacterial diseases (a30-a49).
A36.85 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.
Verify that diphtheria has been confirmed as the causative organism of the cystitis before assigning this code, as it requires documentation of both conditions.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for A36.85 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify that diphtheria has been confirmed as the causative organism of the cystitis before assigning this code, as it requires documentation of both conditions
- •This code should be used only when the cystitis is specifically related to diphtheritic infection; do not use for other bacterial causes of bladder infection