ICD-10 Code E51.8 – Other manifestations of thiamine deficiency (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code E51.8 – Other manifestations of thiamine deficiency
What it is
E51.8 identifies thiamine deficiency when the presentation does not fit a more specific thiamine-deficiency code. Use it for documented manifestations of vitamin B1 deficiency that are not otherwise classified.
Clinical signs
Clinical features vary; refer to documentation. Thiamine deficiency may be associated with neurologic, cardiovascular, or nutritional findings, but you should code this only when the record clearly links the manifestation to thiamine deficiency.
When to use this code
Use E51.8 when the provider documents thiamine deficiency with an atypical or unspecified manifestation and no more specific code applies. It also fits cases where the chart notes a manifestation of thiamine deficiency but does not name beriberi or Wernicke-related disease.
Confirm that the diagnosis is active and clinically relevant, not just a historical low vitamin level. If the documentation is vague, check documentation before assigning this code.
Do not use for
Do not use E51.8 for simple dietary deficiency without a documented manifestation, or when a more specific thiamine-deficiency code is stated. Do not code it for unrelated neurologic or cardiac findings without provider linkage.
Coding tip
Look for the exact wording “other manifestations of thiamine deficiency” or a clearly linked atypical presentation before coding E51.8.