ICD-10 Code E71.42 – Carnitine deficiency due to inborn errors of metabolism (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code E71.42 – Carnitine deficiency due to inborn errors of metabolism
What it is
E71.42 identifies a hereditary disorder in which the body cannot make or use carnitine normally because of an inborn metabolic defect. This code describes primary carnitine deficiency related to metabolism, not an acquired shortage.
Clinical signs
Clinical features vary; refer to documentation. Common findings may include muscle weakness, poor energy, hypoglycemia, cardiomyopathy, or liver involvement in affected patients.
When to use this code
Use E71.42 when the record documents carnitine deficiency caused by an inherited metabolic disorder. Apply it when the diagnosis is confirmed or clearly stated by the clinician, genetics, or metabolic specialist.
Do not use it for nonspecific low carnitine levels without a documented inborn error. If the chart only notes “carnitine deficiency,” check documentation to confirm the cause.
Do not use for
Do not use this code for acquired carnitine deficiency, medication-related deficiency, or malnutrition-related low carnitine. Check documentation if the etiology is not clearly inherited.
Coding tip
Code E71.42 only when the inherited metabolic cause is documented, not just the lab abnormality.