ICD-10 K61.1
Billable / Specific CCRectal abscess
About ICD-10-CM K61.1
ICD-10-CM code K61.1 represents Rectal abscess. This is a billable/specific code in the Digestive System chapter (block K61). The 2026 edition of ICD-10-CM K61.1 became effective on October 1, 2025.
Coding Tips for K61.1
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
K61.1 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 K61.1. Per CMS ICD-10-CM Tabular 2026.
- Perirectal abscess
Type 1 Excludes
Pure excludes, these codes can never be coded together with K61.1. The conditions are mutually exclusive (e.g., congenital vs acquired forms).
- ischiorectal abscess (K61.39)
Inpatient DRG Impact, CC
codes Rectal abscess. As a Complication/Comorbidity (CC), this contributes to DRG severity adjustment when documented alongside the principal diagnosis.
Medicare LCD Coverage for K61.1
Local Coverage Determinations (LCDs) from CMS MACs that list K61.1 as a covered diagnosis.
Showing top 10 of 11 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing K61.1.
2 Medicare
CPT Codes Commonly Billed with K61.1
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 K61.1 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 |
|---|---|---|
| K61.1 | 566 | 10000 |
Flags format (5 digits): Approximate · No Map · Combination · Scenario · Choice List. Source: CMS 2017 GEMs (final version).
Codes Adjacent To K61.1
Other codes in section K55-K64 (Other diseases of intestines).
ICD-10 K61.1, Billing FAQ
Is ICD-10 code K61.1 billable? +
Yes, K61.1 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 K61.1? +
ICD-10 K61.1 includes: Perirectal abscess.
What codes are Type 1 Excludes for K61.1? +
Type 1 Excludes (never code together with K61.1): ischiorectal abscess (K61.39)
Is K61.1 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 K61.1 map to? +
Per CMS GEMs, K61.1 maps to ICD-9 codes: 566. Useful for legacy data review and historical claim analysis.
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Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on May 31, 2026.
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