NBS Phenylketonuria (Phenylalanine)

The Newborn Screening (NBS) test for Phenylketonuria (PKU) measures phenylalanine levels in the blood of newborns. PKU is a rare inherited disorder that prevents the breakdown of phenylalanine, leading to toxic accumulation and brain damage if left untreated.

This test is performed on all newborns as part of routine newborn screening within 24–72 hours after birth. Early detection of PKU allows for timely intervention to prevent intellectual disabilities and developmental delays.

A few drops of blood are collected from the newborn’s heel and placed on a special filter paper card. The sample is analyzed in a laboratory to measure phenylalanine levels. Elevated levels may indicate PKU and require further confirmatory testing.

• Normal result: Indicates phenylalanine levels within the normal range, suggesting the absence of PKU.
• Elevated phenylalanine: May indicate PKU or another metabolic disorder, requiring further confirmatory tests.

Early diagnosis of PKU allows for dietary management through a phenylalanine-restricted diet, preventing intellectual disability and ensuring normal growth and development.