ICD-10 M45.4
Billable / Specific HCC v28: 40Ankylosing spondylitis of thoracic region
About ICD-10-CM M45.4
ICD-10-CM code M45.4 represents Ankylosing spondylitis of thoracic region. This is a billable/specific code in the Musculoskeletal and Connective Tissue chapter (block M45). The 2026 edition of ICD-10-CM M45.4 became effective on October 1, 2025.
Coding Tips for M45.4
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
M45.4 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 M45.4
Local Coverage Determinations (LCDs) from CMS MACs that list M45.4 as a covered diagnosis.
Showing top 10 of 229 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing M45.4.
5 Medicare
CPT Codes Commonly Billed with M45.4
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 M45.4 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 |
|---|---|---|
| M45.4 | 7200 | 10000 |
Flags format (5 digits): Approximate · No Map · Combination · Scenario · Choice List. Source: CMS 2017 GEMs (final version).
Codes Adjacent To M45.4
Other codes in section M45-M49 (Spondylopathies).
ICD-10 M45.4, Billing FAQ
Is ICD-10 code M45.4 billable? +
Yes, M45.4 is a billable ICD-10-CM code that can appear as a primary or secondary diagnosis on claims.
Does M45.4 affect Medicare Advantage HCC risk adjustment? +
Yes. M45.4 maps to CMS-HCC v28 category 40. Capture this diagnosis annually for accurate Medicare Advantage risk score.
What ICD-9 codes does M45.4 map to? +
Per CMS GEMs, M45.4 maps to ICD-9 codes: 7200. 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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