Phenylalanine Neonatal Screen - Dried blood spot Test

This test measures the amount of phenylalanine, an amino acid, in a newborn's blood sample.

• To detect and diagnose phenylketonuria (PKU) soon after birth
• To prevent the development of PKU-related brain damage
• To allow early treatment to keep the levels of phenylalanine low
• To identify carriers of the PKU gene in parents or siblings

This test is recommended for all infants to ensure early detection and treatment of PKU. It is especially important if

• the baby has a family history of PKU or other metabolic disorders,
• the pregnancy was complicated or high risk, or
• the mother had PKU or consumed large amounts of aspartame during pregnancy.

Elevated levels suggest PKU, a rare genetic disorder that affects about one in 10,000 to 20,000 newborns. Further tests are required to confirm the diagnosis.

The procedure is quick and simple and happens before the baby leaves the hospital. Here's what to expect:

• A nurse will prick the baby's heel or finger to collect a few drops of blood.
• The sample will be applied on a special filter paper card.
• The card, with all relevant details, will be sent to the lab for analysis.

• Ensure your baby is well-fed ahead of time so that it doesn't get agitated by hunger during the test.
• Consult your doctor for any specific requirements.

Paediatricians may order additional tests if elevated phenylalanine levels are found. These include:

• Diurnal variations in urine organic acids
• Blood amino acid concentrations
• Urine biopterin levels

These tests can help confirm or rule out PKU.

PKU screening or Guthrie test

PKU or phenylketonuria is a rare inherited disorder that increases phenylalanine levels in the blood. Without early and lifelong treatment, it can cause intellectual disability, seizures, behavioural problems, and even death. Treatment includes a strict low-phenylalanine diet and medication.