2027 ICD-10-CM Diagnosis Code G73.3Myasthenic syndromes in other diseases classified elsewhere
ICD-10-CM Codes›G00–G99›G70-G73›G73
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Risk Adjusts — HCC 196
- Not Chronic
G73.3 is a billable ICD-10-CM diagnosis code for myasthenic syndromes in other diseases classified elsewhere. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 56 through 57. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 72 closely related codes. The code is a manifestation code that cannot be reported as the principal diagnosis. Coders also document this condition as myasthenic syndrome due to another disorder. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Myopathies.
For Medicare Advantage risk adjustment, G73.3 maps to CMS-HCC Category 196 (Myasthenia Gravis without (Acute) Exacerbation and Other Myoneural Disorders) under the V28 model, adding a risk factor of about 0.516 for a community, non-dual, aged beneficiary in payment year 2027.
Code Identity
Code Classification
Code EditsBilling
Medicare Code Editor checks that affect claim validity for G73.3.
Medicare Risk Adjustment (HCC)Billing
G73.3 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2027.
Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Myasthenic syndrome due to another disorder
- Myasthenic syndrome due to hypothyroidism
- Myasthenic syndrome due to pernicious anemia
- Myasthenic syndrome due to thyrotoxicosis
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to G73.3: its own notes plus those printed at Chapter 6. A note printed at a category, block or chapter applies to every code under it.
Excludes2
Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.
- certain conditions originating in the perinatal period (P04-P96)
- certain infectious and parasitic diseases (A00-B99)
- complications of pregnancy, childbirth and the puerperium (O00-O9A)
- congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
- endocrine, nutritional and metabolic diseases (E00-E88)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
Code First
The underlying condition named in the note is sequenced before this code.
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name G73.3, its category, or a range that includes it.
Code First 1
These codes say to code first a condition named in the note, and G73.3 is one of the conditions named.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Myasthenia Gravis
Myasthenia gravis, sometimes called MG, is a chronic (long-lasting) disease that causes weakness in your voluntary muscles. The voluntary muscles are the ones that you can control. They include the muscles you use for:
The full article covers:
- What is myasthenia gravis?
- What causes myasthenia gravis?
- Who is more likely to develop myasthenia gravis?
- What are the symptoms of myasthenia gravis?
- How is myasthenia gravis diagnosed?
- What are the treatments for myasthenia gravis?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert G73.3 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About G73.3Overview
What is the ICD-10 code for myasthenic syndromes in other diseases classified elsewhere?
The ICD-10-CM code for myasthenic syndromes in other diseases classified elsewhere is G73.3 (sometimes written as G733). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is G73.3 a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report myasthenic syndromes in other diseases classified elsewhere on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does G73.3 group to?
On inpatient claims, myasthenic syndromes in other diseases classified elsewhere maps to MS-DRG 57, 56, with relative weights from 1.2835 to 2.2649 depending on complications. Higher weights mean higher Medicare reimbursement.
Is G73.3 a CC or MCC?
CMS lists G73.3 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 72 closely related codes in its exclusion list.
Can G73.3 be a principal diagnosis?
No. This is a manifestation code: myasthenic syndromes in other diseases classified elsewhere describes the manifestation of an underlying disease rather than the disease itself, so the underlying condition is sequenced first.
What HCC is G73.3?
G73.3 (myasthenic syndromes in other diseases classified elsewhere) maps to CMS-HCC Category 196 (Myasthenia Gravis without (Acute) Exacerbation and Other Myoneural Disorders), commonly written as HCC 196, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2027. It mapped to HCC 75 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. In the Part D prescription drug model it maps to RxHCC 153.
Does G73.3 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, G73.3 adds a risk adjustment factor of about 0.516 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.248 to 0.642 depending on the payment segment). A more severe related category (HCC 195) supersedes it when both are reported. See the full factor table on the HCC 196 category page.
