ICD-10-CM 2027
ICD-10 code for myasthenia
From the official ICD-10-CM alphabetic index entry “Myasthenia”. Page updated September 29, 2026.
About coding myasthenia
The ICD-10-CM code for myasthenia is G70.9 (Myoneural disorder, unspecified). The official index lists 14 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on G70.9.
Within G70, choose G70.9 (Myoneural disorder, unspecified) only when documentation doesn't support a more specific option: myasthenia gravis (G70.0), toxic myoneural disorders (G70.1), congenital and developmental myasthenia (G70.2) and other specified myoneural disorders (G70.8).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 073 (Cranial and Peripheral Nerve Disorders with MCC, relative weight 1.5779) and DRG 074 (Cranial and Peripheral Nerve Disorders without MCC, relative weight 1.0173), in MDC 01 (Diseases and Disorders of the Nervous System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
More specific myasthenia codes (official index)
- congenital G70.2 — Congenital and developmental myasthenia
- cordis
- developmental G70.2 — Congenital and developmental myasthenia
- gravis G70.00 — Myasthenia gravis without (acute) exacerbation
- with exacerbation (acute) G70.01 — Myasthenia gravis with (acute) exacerbation
- in crisis G70.01 — Myasthenia gravis with (acute) exacerbation
- neonatal, transient P94.0 — Transient neonatal myasthenia gravis
- pseudoparalytica G70.00 — Myasthenia gravis without (acute) exacerbation
- with exacerbation (acute) G70.01 — Myasthenia gravis with (acute) exacerbation
- in crisis G70.01 — Myasthenia gravis with (acute) exacerbation
- stomach, psychogenic F45.8 — Other somatoform disorders
- syndrome
- in
- diabetes mellitus
- neoplastic disease D49.9 — Neoplasm of unspecified behavior of unspecified site
- pernicious anemia D51.0 — Vitamin B12 deficiency anemia due to intrinsic factor deficiency
- thyrotoxicosis E05.90 — Thyrotoxicosis, unspecified without thyrotoxic crisis or storm
- with thyroid storm E05.91 — Thyrotoxicosis, unspecified with thyrotoxic crisis or storm
Common questions about myasthenia ICD-10 codes
What is the ICD-10 code for myasthenia?
- G70.9 — Myoneural disorder, unspecified. More specific codes apply when the documentation supports them: G70.2, G70.2, G70.00, G70.01 and others below.
What is the ICD-10 code for congenital myasthenia?
- G70.2 — Congenital and developmental myasthenia.
What is the ICD-10 code for developmental myasthenia?
- G70.2 — Congenital and developmental myasthenia.
What is the ICD-10 code for gravis myasthenia?
- G70.00 — Myasthenia gravis without (acute) exacerbation.
Is G70.9 billable?
- Yes. G70.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can G70.9 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict G70.9 as a principal diagnosis.
Is G70.9 a CC or MCC?
- No. G70.9 is neither a CC nor an MCC under MS-DRG v44.0.