ICD-10 Code E70.4 – Disorders of histidine metabolism (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code E70.4 – Disorders of histidine metabolism
What it is
E70.4 identifies inherited disorders that affect the body’s ability to process histidine, an amino acid. Use it when documentation specifies a histidine metabolism disorder, not a broader amino acid condition.
Clinical signs
Clinical features vary; refer to documentation. These disorders may be recognized through developmental concerns, neurologic findings, or abnormal metabolic screening consistent with impaired histidine handling.
When to use this code
Use E70.4 when the provider documents a confirmed disorder of histidine metabolism, including a specific inherited enzyme defect in this pathway. It may also apply when the record names a histidine-related metabolic disorder without a more precise code. Check documentation if the diagnosis is only suspected or if a different amino acid disorder is described.
Do not use for
Do not use this code for general amino acid metabolism disorders, nonspecific metabolic screening abnormalities, or conditions unrelated to histidine. If the chart does not clearly identify histidine metabolism involvement, check documentation.
Coding tip
Code E70.4 only when the provider links the disorder specifically to histidine metabolism; otherwise, query for clarification.