ICD-10 Code G56.90 – Unspecified mononeuropathy of unspecified upper limb (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G56.90 – Unspecified mononeuropathy of unspecified upper limb
What it is
Use this code for a single peripheral nerve disorder in an upper limb when the chart does not identify the exact nerve or a more specific mononeuropathy. It indicates an unspecified location and type within the upper extremity.
Clinical signs
Clinical features vary; refer to documentation. Typical findings may include localized numbness, tingling, weakness, or pain in one upper limb nerve distribution, with exam or testing supporting a mononeuropathy.
When to use this code
Use G56.90 when the provider documents mononeuropathy of the upper limb but does not name the nerve involved or provide a more specific diagnosis. It also fits when laterality or exact site is not available in the record. Choose a more specific code if the documentation identifies the median, ulnar, radial, or another named nerve.
Do not use for
Do not use this code for carpal tunnel syndrome, generalized polyneuropathy, or mononeuropathy with a clearly identified nerve and site. Check documentation if the record supports a more specific upper-limb neuropathy code.
Coding tip
Before assigning G56.90, verify whether the note names the affected nerve or laterality, because a more specific code is usually available.