ICD-10 Code E70.1 – Other hyperphenylalaninemias (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code E70.1 – Other hyperphenylalaninemias
What it is
E70.1 identifies other forms of hyperphenylalaninemia, a group of inherited disorders where phenylalanine builds up because normal metabolism is impaired. Use it when the record specifies a non-PKU hyperphenylalaninemia or another related condition.
Clinical signs
Clinical features vary; refer to documentation. Common references describe elevated phenylalanine on testing, with possible developmental or neurologic concerns depending on severity and timing of diagnosis.
When to use this code
Use E70.1 when the clinician documents other hyperphenylalaninemia, atypical hyperphenylalaninemia, or a related inherited phenylalanine metabolism disorder that is not coded as classic phenylketonuria. Apply it when the diagnosis is confirmed or clearly stated in the chart. Check documentation if the note only mentions abnormal newborn screening without a final diagnosis.
Do not use for
Do not use this code for classic phenylketonuria if the record specifies that diagnosis. Do not assign it for an isolated abnormal laboratory result without a documented metabolic disorder.
Coding tip
Code the most specific inherited phenylalanine disorder documented, and verify whether the provider distinguishes it from PKU.