ICD-10 Code E71.120 – Methylmalonic acidemia (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code E71.120 – Methylmalonic acidemia
What it is
Methylmalonic acidemia is an inherited metabolic disorder in which the body cannot properly process certain fats and proteins. It leads to buildup of methylmalonic acid and related metabolic products.
Clinical signs
Clinical features vary; refer to documentation. Common findings may include recurrent vomiting, poor feeding, lethargy, developmental delay, and episodes of metabolic decompensation.
When to use this code
Use E71.120 when the record clearly documents methylmalonic acidemia as the confirmed diagnosis. It may also apply when the condition is being followed long term as a known inherited disorder. Code the documented subtype or associated disorder separately if the record supports it.
Do not use for
Do not use this code for isolated elevated methylmalonic acid without a diagnosis of methylmalonic acidemia. Check documentation if the note only states suspected metabolic disorder or abnormal screening results.
Coding tip
Confirm the provider’s final diagnosis and avoid coding from laboratory abnormalities alone.