ICD-10 M46.1
Billable / Specific HCC v28: 40Sacroiliitis, not elsewhere classified
About ICD-10-CM M46.1
ICD-10-CM code M46.1 represents Sacroiliitis, not elsewhere classified. This is a billable/specific code in the Musculoskeletal and Connective Tissue chapter (block M46). The 2026 edition of ICD-10-CM M46.1 became effective on October 1, 2025.
Coding Tips for M46.1
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
M46.1 is a CMS-HCC v28 risk-adjustment code (category 40). 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.
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.
Medicare LCD Coverage for M46.1
Local Coverage Determinations (LCDs) from CMS MACs that list M46.1 as a covered diagnosis.
Showing top 10 of 483 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing M46.1.
2 Aetna
1 Cigna
5 Medicare
CPT Codes Commonly Billed with M46.1
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
- 64493 Facet joint injection lumbar L1 — back pain, spondylosis, sacrococcygeal disorder, sacroiliitis, spinal stenosis Pain Management
- 27096 CMS LCD: Billing and Coding: Sacroiliac Joint Injections and Procedures CMS LCD
- G0260 CMS LCD: Billing and Coding: Sacroiliac Joint Injections and Procedures CMS LCD
- 64451 CMS LCD: Billing and Coding: Sacroiliac Joint Injections and Procedures CMS LCD
- 64625 CMS LCD: Billing and Coding: Sacroiliac Joint Injections and Procedures CMS LCD
- 27279 CMS LCD: Billing and Coding: Minimally Invasive Arthrodesis of the Sacroiliac Joint (SIJ) CMS LCD
- 27278 CMS LCD: Billing and Coding: Minimally Invasive Arthrodesis of the Sacroiliac Joint (SIJ) CMS LCD
Convert M46.1 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 |
|---|---|---|
| M46.1 | 7202 | 00000 |
Flags format (5 digits): Approximate · No Map · Combination · Scenario · Choice List. Source: CMS 2017 GEMs (final version).
Codes Adjacent To M46.1
Other codes in section M45-M49 (Spondylopathies).
ICD-10 M46.1, Billing FAQ
Is ICD-10 code M46.1 billable? +
Yes, M46.1 is a billable ICD-10-CM code that can appear as a primary or secondary diagnosis on claims.
Does M46.1 affect Medicare Advantage HCC risk adjustment? +
Yes. M46.1 maps to CMS-HCC v28 category 40. Capture this diagnosis annually for accurate Medicare Advantage risk score.
What CPT codes are commonly billed with M46.1? +
Procedures frequently paired with M46.1 include: 64493, 27096, G0260, 64451, 64625.
What ICD-9 codes does M46.1 map to? +
Per CMS GEMs, M46.1 maps to ICD-9 codes: 7202. 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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