Screening Programs for EarlyDetection of Inborn Errors ofMetabolism in Neonates

KEY POINTS

• 1.

  Should protein in the diet be limited while waiting for results? No. It is not recommended to change the diet to a specialized diet without confirmation of results. However, if the baby is critically ill, it may be recommended to stop feeds due to instability. It is not recommended to stop all protein for more than 24 to 48 hours in patients with inborn errors of metabolism, due to the risk of catabolism. It is imperative to work fast to confirm the newborn screen results and be able to appropriately manage the baby.

• 2.

  Is carnitine added to total parenteral nutrition (TPN) adequate as a supplement? The amount added to TPN is below the recommended dosage for carnitine uptake deficiency. It may be sufficient to affect newborn screen results. Therefore it is sometimes recommended to stop TPN for hours before sending testing.

• 3.

  How long to hold TPN prior to blood or urine collection? There is no evidence-based literature on the perfect timing. Many state labs will recommend waiting for 48 hours after TPN has been discontinued. However, many labs will recommend to provide Intravenous Fluids (IVF) without amino acids for 3 to 4 hours prior to drawing confirmatory testing.

• 4.

  Can the baby be discharged before the results come back? It depends on the disorder for which the baby is being evaluated. It is best to communicate with the referral center prior to discharging baby.