G71.3 ICD-10-CM Code: Mitochondrial myopathy, not elsewhere classified
HCC Buddy Code Card
Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.
FY 2026 Apr update / Diseases of the nervous system (G00-G99) / Diseases of myoneural junction and muscle (G70-G73)
G71.3
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceMitochondrial myopathy, not elsewhere classified
A rare muscle disease caused by problems with mitochondria (the energy-producing parts of muscle cells), resulting in muscle weakness and fatigue that cannot be classified under other specific mitochondrial conditions. Symptoms typically worsen with physical activity as muscles cannot produce enough energy to function properly.
CMS-HCC V28
00
RAF 0
CMS-HCC V24
00
RAF 0
ACA/HHS
00
RAF 0
ESRD/PACE
00
RAF 0
RXHCC
00
RAF 0
Code Trumping
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Code Book Path
Inclusion Terms
OfficialICD-10-CM does not list inclusion terms for G71.3 in this effective period.
Excludes 2
Official- arthrogryposis multiplex congenita (Q74.3)
- metabolic disorders (E70-E88)
- myositis (M60.-)
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for G71.3 in this effective period.
Excludes 1
Official- Kearns-Sayre syndrome (H49.81)
- Leber's disease (H47.21)
- Leigh's encephalopathy (G31.82)
- mitochondrial metabolism disorders (E88.4.-)
- Reye's syndrome (G93.7)
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for G71.3 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for G71.3 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for G71.3 in this effective period.
Buddy Documentation Tip
Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.
Is G71.3 an HCC code?
No. G71.3 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
G71.3 is the ICD-10-CM diagnosis code for mitochondrial myopathy, not elsewhere classified. A rare muscle disease caused by problems with mitochondria (the energy-producing parts of muscle cells), resulting in muscle weakness and fatigue that cannot be classified under other specific mitochondrial conditions. Symptoms typically worsen with physical activity as muscles cannot produce enough energy to function properly. G71.3 sits in the ICD-10-CM chapter for diseases of the nervous system (g00-g99), within the section covering diseases of myoneural junction and muscle (g70-g73).
G71.3 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.
Verify that the mitochondrial myopathy does not fit into more specific categories (G71.0, G71.1, or G71.2) before assigning G71.3, as this is a 'not elsewhere classified' code.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for G71.3 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify that the mitochondrial myopathy does not fit into more specific categories (G71.0, G71.1, or G71.2) before assigning G71.3, as this is a 'not elsewhere classified' code
- •Document the specific muscles affected and any associated symptoms (exercise intolerance, fatigue, weakness) in the medical record to support medical necessity and severity