ICD-10 Code for fibromyalgia

The ICD-10-CM code for fibromyalgia is M79.7 when documented without further specification. Fibromyalgia codes to M79.7, a single complete code with no laterality or further subdivision. It sits in the soft-tissue disorder category M79 alongside myalgia (M79.1-) and unspecified rheumatism (M79.0), which are distinct conditions.

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Symptom code vs. confirmed diagnosis

Fibromyalgia (M79.7) is a clinical diagnosis, not a symptom. Generalized muscle pain without a fibromyalgia diagnosis is coded as myalgia (M79.1-); assign M79.7 only when the provider documents fibromyalgia.

Which Code Should You Use?

M79.7 ✓ Billable — Fibromyalgia

Fibromyalgia documented as the diagnosis.

M79.0 ✓ Billable — Rheumatism, unspecified

Rheumatism, unspecified.

M79.10 ✓ Billable — Myalgia, unspecified site

Myalgia, unspecified site.

M79.18 ✓ Billable — Myalgia, other site

Myalgia, other site.

What to Document

  • That fibromyalgia is the provider's documented diagnosis (versus generalized myalgia).
  • Any localized muscle pain that is better captured as myalgia (M79.1-).
  • Coexisting conditions (e.g., fatigue or mood disorders) when separately documented.

Common Documentation Pitfalls

  • Coding widespread muscle pain as fibromyalgia (M79.7) when the provider documents only myalgia (M79.1-).
  • M79.7 has no laterality or additional characters — do not seek a site-specific subcode.

Also Known As

Official ICD-10-CM Alphabetic Index terms that point to M79.7:

  • Myofibrositis
  • Fibromyalgia
  • Fibromyositis
  • Fibrositis (periarticular)

Coding Notes

M79.7 is a complete, billable code for fibromyalgia with no laterality. Distinguish it from myalgia (M79.1-), which is muscle pain without a fibromyalgia diagnosis. Code coexisting conditions separately when documented.

References

Reviewed by Prajwal Shrestha, CPC, CRC
Certified Professional Coder (CPC) and Certified Risk Adjustment Coder (CRC) · AAPC Member ID 01997614 · About · Editorial policy · Content last reviewed: 2025-10-01

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