ICD-10 M79.A21
Billable / Specific CCNontraumatic compartment syndrome of right lower extremity
About ICD-10-CM M79.A21
ICD-10-CM code M79.A21 represents Nontraumatic compartment syndrome of right lower extremity. This is a billable/specific code in the Musculoskeletal and Connective Tissue chapter (block M79). The 2026 edition of ICD-10-CM M79.A21 became effective on October 1, 2025.
Coding Tips for M79.A21
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
M79.A21 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.
Inpatient DRG Impact, CC
codes Nontraumatic compartment syndrome of right lower extremity. As a Complication/Comorbidity (CC), this contributes to DRG severity adjustment when documented alongside the principal diagnosis.
Medicare LCD Coverage for M79.A21
Local Coverage Determinations (LCDs) from CMS MACs that list M79.A21 as a covered diagnosis.
Showing top 10 of 187 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing M79.A21.
3 Medicare
CPT Codes Commonly Billed with M79.A21
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 M79.A21 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 |
|---|---|---|
| M79.A21 | 72972 | 10000 |
Flags format (5 digits): Approximate · No Map · Combination · Scenario · Choice List. Source: CMS 2017 GEMs (final version).
Codes Adjacent To M79.A21
Other codes in section M70-M79 (Other soft tissue disorders).
ICD-10 M79.A21, Billing FAQ
Is ICD-10 code M79.A21 billable? +
Yes, M79.A21 is a billable ICD-10-CM code that can appear as a primary or secondary diagnosis on claims.
Is M79.A21 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 M79.A21 map to? +
Per CMS GEMs, M79.A21 maps to ICD-9 codes: 72972. 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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