Transitory hyperammonemia of newborn

This code signifies a temporary elevation of ammonia levels in a newborn's blood, typically resolving spontaneously within the first few days of life. It is a benign condition distinct from inherited metabolic disorders causing hyperammonemia.

Apply this code when documentation indicates a newborn with elevated ammonia levels that are transient and not attributable to a primary metabolic defect or other underlying pathology. Supporting documentation should confirm the hyperammonemia and its resolution without specific intervention for a metabolic disorder.

• Differentiate from hyperammonemia due to inborn errors of metabolism (e.g., urea cycle disorders), which require specific codes.
• Ensure documentation explicitly states "transitory" or "transient" hyperammonemia of newborn.
• Do not use if the hyperammonemia is secondary to another condition, such as sepsis or liver failure.