E70.1

HCC Category Mapping

What This Code Means

A group of inherited metabolic conditions where phenylalanine levels are elevated in the blood but not as severe as classical phenylketonuria.

Coding Tips

• •Distinguish between classical PKU (E70.0) and other hyperphenylalaninemias (E70.1)
• •Document the specific type of hyperphenylalaninemia when available (benign, mild, or variant forms)

Clinical Significance

Other hyperphenylalaninemias include milder forms of elevated blood phenylalanine that do not reach the severity of classical phenylketonuria, such as benign hyperphenylalaninemia and biopterin cofactor deficiencies. These conditions may require less restrictive dietary management than classical phenylketonuria but still necessitate ongoing monitoring to prevent neurological complications, particularly in women of childbearing age due to maternal hyperphenylalaninemia risks.

Documentation Requirements

• ✓Documentation should specify the type of hyperphenylalaninemia (benign, mild, variant, or biopterin-responsive), phenylalanine blood levels with target ranges, biopterin loading test results if applicable, current dietary management status, and neurological assessment.
• ✓For women of reproductive age, documentation should address maternal phenylketonuria counseling.
• ✓Distinguish clearly from classical phenylketonuria in the medical record.

Commonly Confused Codes