ICD-10 Code G70.81 – Lambert-Eaton syndrome in disease classified elsewhere (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G70.81 – Lambert-Eaton syndrome in disease classified elsewhere
What it is
This code identifies Lambert-Eaton syndrome when it is documented as occurring secondary to another disease. It is a neuromuscular junction disorder that causes impaired muscle activation.
Clinical signs
Typical findings include proximal muscle weakness, reduced reflexes, and possible autonomic symptoms such as dry mouth. Clinical features vary; refer to documentation.
When to use this code
Use G70.81 when the provider documents Lambert-Eaton syndrome as associated with a separate underlying condition, such as a malignancy or other disease. Code the underlying condition first when required by sequencing rules. If the record does not clearly link the syndrome to another disease, check documentation.
Do not use for
Do not use this code for Lambert-Eaton syndrome without documentation of an associated disease. Do not confuse it with myasthenia gravis or other neuromuscular disorders.
Coding tip
Verify the causal relationship and sequence the underlying disease correctly before assigning G70.81.