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ICD-10-CM 2027 diagnosis code

G73.1Lambert-Eaton syndrome in neoplastic disease

✓ Billable / specificCC — complication/comorbidityManifestation — not principalNot a principal dx

G73.1 is a valid, billable ICD-10-CM code for lambert-eaton syndrome in neoplastic disease. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About G73.1

G73.1 is the ICD-10-CM diagnosis code for Lambert-Eaton syndrome in neoplastic disease. It belongs to category G73 (disorders of myoneural junction and muscle in diseases classified elsewhere), block G70-G73 (diseases of myoneural junction and muscle) and chapter 6 (diseases of the nervous system). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within G73 (disorders of myoneural junction and muscle in diseases classified elsewhere), G73.1 is specifically for Lambert-Eaton syndrome in neoplastic disease. Related codes cover Myasthenic syndromes in other diseases classified elsewhere (G73.3) and myopathy in diseases classified elsewhere (G73.7).

Don't report G73.1 together with the conditions in its Excludes1 note: Lambert-Eaton syndrome not associated with neoplasm (G70.80-G70.81).

Code first: underlying neoplasm (C00-D49).

As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.

In MS-DRG v44.0, it is part of the grouping logic for DRG 056 (Degenerative Nervous System Disorders with MCC, relative weight 2.2655) and DRG 057 (Degenerative Nervous System Disorders without MCC, relative weight 1.2838), 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.

It is a manifestation code, so it describes the effect of an underlying disease and can't be the principal diagnosis. Code the underlying condition first.

It is not acceptable as the principal diagnosis for an inpatient stay; it may be reported as a secondary diagnosis.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 358.31 (Lambert-Eaton syndrome in neoplastic disease).

Coding notes

Excludes1Not coded here — never report together with this code
  • Lambert-Eaton syndrome not associated with neoplasm (G70.80-G70.81)
Code firstSequence the underlying condition first

Notes that apply from higher levels

Instructions written at a parent level also apply to G73.1.

Broader instructions also apply from Chapter 6: Diseases of the nervous system.

Alphabetic index entries

1 entries

Terms in the official ICD-10-CM index that lead to G73.1.

Codes whose notes reference G73.1

MS-DRG v44.0 grouping

All DRGs →

Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.

ICD-9-CM equivalent

Converter →
  • 358.31Lambert-Eaton syndrome in neoplastic diseaseexact

From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about G73.1

Is G73.1 billable?

Yes. G73.1 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can G73.1 be used as a principal diagnosis?

No. It is a manifestation code, so it describes the effect of an underlying disease and can't be the principal diagnosis. Code the underlying condition first.

Is G73.1 a CC or MCC?

G73.1 is a CC (complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.

What DRG does G73.1 group to?

G73.1 is used in the MS-DRG v44.0 logic for MS-DRG 056 (Degenerative Nervous System Disorders with MCC) and MS-DRG 057 (Degenerative Nervous System Disorders without MCC). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.

What is the ICD-9 code for G73.1?

The CMS General Equivalence Mappings map G73.1 to ICD-9-CM 358.31.