ICD-10 K91.850
Billable / Specific HCC v28: 188 CCPouchitis
About ICD-10-CM K91.850
ICD-10-CM code K91.850 represents Pouchitis. This is a billable/specific code in the Digestive System chapter (block K91). The 2026 edition of ICD-10-CM K91.850 became effective on October 1, 2025.
Coding Tips for K91.850
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
K91.850 is a CMS-HCC v28 risk-adjustment code (category 188). To count for the patient Risk Adjustment Factor (RAF), document the diagnosis with MEAT language each calendar year: Monitored, Evaluated, Assessed, Treated. A diagnosis on the problem list alone does not satisfy CMS RADV audit standards. Include the diagnosis in the assessment with current status and current treatment plan.
K91.850 is designated CC for MS-DRG grouping. On inpatient claims, this code can shift the DRG to the with-CC variant when documented as a present-on-admission secondary diagnosis. Hospital CDI programs flag CC opportunities during chart review. Failure to capture this code may leave 30 to 80 percent of the inpatient stay revenue unrealized.
Inclusion Terms / Approximate Synonyms
Clinical terms and conditions classified under K91.850. Per CMS ICD-10-CM Tabular 2026.
- Inflammation of internal ileoanal pouch
Medicare Advantage HCC Impact
Capture this diagnosis annually for accurate risk adjustment. Missed HCC captures are the #1 revenue leak in Medicare Advantage risk programs.
Inpatient DRG Impact, CC
codes Pouchitis. As a Complication/Comorbidity (CC), this contributes to DRG severity adjustment when documented alongside the principal diagnosis.
Medicare LCD Coverage for K91.850
Local Coverage Determinations (LCDs) from CMS MACs that list K91.850 as a covered diagnosis.
Showing top 10 of 186 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing K91.850.
5 Medicare
CPT Codes Commonly Billed with K91.850
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
We don't have CPT pairings indexed for this specific code yet. Use the CPT search above to find common procedures, or check your payer's published medical policy for code-specific guidance.
Convert K91.850 to ICD-9-CM
Per CMS General Equivalence Mappings (GEMs), useful for legacy data review and historical claim analysis.
| ICD-10 | ICD-9 | Mapping Flags |
|---|---|---|
| K91.850 | 56971 | 00000 |
Flags format (5 digits): Approximate · No Map · Combination · Scenario · Choice List. Source: CMS 2017 GEMs (final version).
Codes Adjacent To K91.850
Other codes in section K90-K95 (Other diseases of the digestive system).
ICD-10 K91.850, Billing FAQ
Is ICD-10 code K91.850 billable? +
Yes, K91.850 is a billable ICD-10-CM code that can appear as a primary or secondary diagnosis on claims.
What other names or terms map to K91.850? +
ICD-10 K91.850 includes: Inflammation of internal ileoanal pouch.
Does K91.850 affect Medicare Advantage HCC risk adjustment? +
Yes. K91.850 maps to CMS-HCC v28 category 188. Capture this diagnosis annually for accurate Medicare Advantage risk score.
Is K91.850 a CC or MCC for inpatient DRG? +
Yes, this code is designated as CC. Documenting as a secondary diagnosis on inpatient claims can shift the DRG to a higher-weighted category.
What ICD-9 codes does K91.850 map to? +
Per CMS GEMs, K91.850 maps to ICD-9 codes: 56971. Useful for legacy data review and historical claim analysis.
Get the full PayerReady toolkit
Free access to CPT/ICD-10 lookup, denial appeals, fee comparator, and claim auditing with credentialing enrollment.
Start free →Run this code through our claim audit tool
Check NCCI bundling, MUE limits, and modifier logic before submission.
Try the auditor →Did this page help?
Quick signal so we know what to improve.
If you want a code reference page that doesn't exist yet, email coding@payerready.com.
Tell us what's missing or wrong: coding@payerready.com. We respond within 5 business days.
Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on June 1, 2026.
Powered by 11K CPT · 98K ICD-10 · 860K MPFS rates · 4.5M NCCI edits · 9.5M NPIs. Our data methodology · About our coding team