2026 ICD-10-CM Diagnosis Code G59Mononeuropathy in diseases classified elsewhere
ICD-10-CM Codes›G00–G99›G50-G59›G59
- Billable — Valid for Submission
- Chronic Condition
G59 is a billable ICD-10-CM diagnosis code for mononeuropathy in diseases classified elsewhere. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). The code is a manifestation code that cannot be reported as the principal diagnosis. Coders also document this condition as neuropathy in arteriosclerotic occlusive disease. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Nerve and nerve root disorders.
Code Identity
Code Classification
Code EditsBilling
Medicare Code Editor checks that affect claim validity for G59.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Neuropathy in arteriosclerotic occlusive disease
- Neuropathy in thromboangiitis obliterans
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Code First
- underlying disease
Type 1 Excludes
- diabetic mononeuropathy E08 E13
- syphilitic nerve paralysis A52.19
- syphilitic neuritis A52.15
- tuberculous mononeuropathy A17.83
Certain conditions have both an underlying etiology and multiple body system manifestations due to the underlying etiology. For such conditions, the ICD-10-CM has a coding convention that requires the underlying condition be sequenced first followed by the manifestation. Wherever such a combination exists, there is a "use additional code" note at the etiology code, and a "code first" note at the manifestation code. These instructional notes indicate the proper sequencing order of the codes, etiology followed by manifestation.
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Peripheral Nerve Disorders
Nerves are like wires that carry messages back and forth between your brain and your body. Your peripheral nerves branch off from your brain and spinal cord and connect to all parts of your body, including your muscles and organs.
The full article covers:
- What are peripheral nerves?
- What are peripheral nerve disorders?
- What causes peripheral nerve disorders?
- What are the symptoms of peripheral nerve disorders?
- How are peripheral nerve disorders diagnosed?
- What are the treatments for peripheral nerve disorders?
- Can peripheral nerve disorders be prevented?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert G59 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About G59Overview
Is G59 (Mononeuropathy in diseases classified elsewhere) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report mononeuropathy in diseases classified elsewhere on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
Can G59 be a principal diagnosis?
No. This is a manifestation code: mononeuropathy in diseases classified elsewhere describes the manifestation of an underlying disease rather than the disease itself, so the underlying condition is sequenced first.
What is the ICD-9 equivalent of G59?
Under the General Equivalence Mappings, mononeuropathy in diseases classified elsewhere converts to ICD-9-CM 355.9 (mononeuritis NOS). The mapping is approximate, so confirm the match fits the documentation.
Footnotes
[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:
- The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
- The condition places limitations on self-care, independent living, and social interactions.
