G70.00 ICD-10-CM Code: Myasthenia gravis without (acute) exacerbation
G70.00 maps to CMS-HCC V28 196. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · HCC coding software
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FY 2026 Apr update / Diseases of the nervous system (G00-G99) / Diseases of myoneural junction and muscle (G70-G73)
G70.00
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceMyasthenia gravis without (acute) exacerbation
A chronic autoimmune condition where muscles become weak and tire easily because the immune system interferes with nerve-muscle communication, currently without acute worsening.
Buddy Insight
Myasthenia gravis without acute exacerbation is a chronic autoimmune neuromuscular disorder that requires lifelong immunosuppressive therapy, cholinesterase inhibitors, and regular monitoring.
CMS-HCC V28
MappedHCC 196
Code-level coefficient reference
CMS-HCC V24
HistoricalHistorical
Not used for CY2026 payment
ACA/HHS
MappedHCC 115
Code-level coefficient reference
ESRD/PACE
MappedHCC 75
Code-level coefficient reference
RXHCC
MappedHCC 153
Code-level coefficient reference
Code Book Path
Inclusion Terms
Official- Myasthenia gravis NOS
Excludes 2
Official- certain conditions originating in the perinatal period (P04-P96)Inherited from G00-G99
- certain infectious and parasitic diseases (A00-B99)Inherited from G00-G99
- complications of pregnancy, childbirth and the puerperium (O00-O9A)Inherited from G00-G99
- congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)Inherited from G00-G99
- endocrine, nutritional and metabolic diseases (E00-E88)Inherited from G00-G99
- injury, poisoning and certain other consequences of external causes (S00-T88)Inherited from G00-G99
- neoplasms (C00-D49)Inherited from G00-G99
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)Inherited from G00-G99
Related Codes
Includes
OfficialNo Includes notes are included in this display for G70.00. Check the code and parent instructions in the Code Book.
Excludes 1
Official- botulism (A05.1, A48.51-A48.52)Inherited from G70
- transient neonatal myasthenia gravis (P94.0)Inherited from G70
Code First
OfficialNo Code First sequencing instructions are included in this display for G70.00. Check the code and parent instructions in the Code Book.
Use Additional
OfficialNo Use Additional Code instructions are included in this display for G70.00. Check the code and parent instructions in the Code Book.
Code Also
OfficialNo Code Also instructions are included in this display for G70.00. Check the code and parent instructions in the Code Book.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
Is G70.00 an HCC code?
Yes. G70.00 (Myasthenia gravis without (acute) exacerbation) maps to HCC 196, Myasthenia Gravis without (Acute) Exacerbation and Other Myoneural Disorders under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 0.516. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.
Coder answer: G70.00 is billable and maps to V28 HCC 196, Myasthenia Gravis without (Acute) Exacerbation and Other Myoneural Disorders. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.
- Code
- G70.00
- Description
- Myasthenia gravis without (acute) exacerbation
- HCC (V28)
- HCC 196 — Myasthenia Gravis without (Acute) Exacerbation and Other Myoneural Disorders
- RAF reference coefficient
- 0.516
- Billable
- Yes
- Payment year
- 2026
HCC Category Mapping
These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. Weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.
Work G70.00 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →
MEAT review for G70.00
For G70.00, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.
- MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
- EEvaluate: test results, medication response, or physical findings reviewed by the provider
- AAssess: explicit mention in the assessment or plan with acknowledgment of status
- TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis
Coder workflow notes
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What This Code Means
G70.00 is the ICD-10-CM diagnosis code for myasthenia gravis without (acute) exacerbation. A chronic autoimmune condition where muscles become weak and tire easily because the immune system interferes with nerve-muscle communication, currently without acute worsening. G70.00 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).
Under the CMS-HCC V28 risk adjustment model, G70.00 maps to Myasthenia Gravis without (Acute) Exacerbation and Other Myoneural Disorders (HCC 196) with a source-labeled community, non-dual, aged reference coefficient of 0.516. No V24 mapping is shown for G70.00; use the applicable model and payment year when reviewing the V28 mapping. For CY2026 non-PACE Medicare Advantage, CMS uses 100% of the 2024 CMS-HCC model (V28). PACE uses a separate model blend. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.
Distinguish between G70.00 (without exacerbation) and G70.01 (with exacerbation) based on current clinical status. For G70.00, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.
HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for G70.00 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Distinguish between G70.00 (without exacerbation) and G70.01 (with exacerbation) based on current clinical status
- •Document muscle weakness patterns and any recent changes in symptoms to support appropriate code selection
Clinical Significance
Myasthenia gravis without acute exacerbation is a chronic autoimmune neuromuscular disorder that requires lifelong immunosuppressive therapy, cholinesterase inhibitors, and regular monitoring. It significantly impacts daily functioning through fluctuating muscle weakness. As a high-value HCC code in both V24 and V28, accurate capture is critical for reflecting the ongoing treatment costs and care complexity of these patients.
Documentation Requirements
- ✓Confirmed diagnosis of myasthenia gravis: positive acetylcholine receptor or anti-MuSK antibodies
- ✓Current disease status: stable, controlled, not in acute exacerbation
- ✓Pattern of muscle weakness: ocular, bulbar, generalized
- ✓Current medication regimen: pyridostigmine, immunosuppressants, corticosteroids
- ✓Functional status assessment: swallowing, respiratory function, daily activity limitations
- ✓Provider's explicit documentation of myasthenia gravis without exacerbation
Commonly Confused Codes
- •G70.01: Myasthenia gravis with acute exacerbation is for worsening symptoms, crisis, or decompensation; use G70.00 when stable
- •G70.2: Congenital and developmental myasthenia is present from birth and has a different pathophysiology (non-autoimmune)
- •G70.80: Lambert-Eaton syndrome is a different autoimmune neuromuscular disorder with distinct antibody profile and treatment
- •G70.9: Myoneural disorder, unspecified should never be used when myasthenia gravis is specifically documented