What is the recommended frequency for bilirubin (blood bilirubin level) testing in a neonate undergoing phototherapy for hyperbilirubinemia?

From the Guidelines

Bilirubin levels should be checked every 2 hours from the start of the escalation of care period until the escalation of care period ends, and otherwise, the frequency of testing should be guided by the TSB trajectory and infant age, with more frequent monitoring for infants with severe hyperbilirubinemia or those at high risk of rebound hyperbilirubinemia. The American Academy of Pediatrics recommends that total serum bilirubin (TSB) should be used as the definitive diagnostic test to guide all interventions, and TSB should be measured if the transcutaneous bilirubin (TcB) reading is within 3.0 mg/dL of the phototherapy treatment threshold, if the TcB exceeds the phototherapy treatment threshold, or if the TcB is ≥15 mg/dL 1. For hospitalized infants, TSB should be measured to verify efficacy after starting phototherapy, with the timing of TSB testing guided by the TSB trajectory and infant age 1. Some key considerations for the frequency of bilirubin testing include:

• The initial bilirubin level and rate of rise
• The age of the infant
• The response to treatment
• The risk of rebound hyperbilirubinemia
• The presence of severe hyperbilirubinemia or hemolysis According to the most recent guidelines, intensive phototherapy can reduce TSB levels and decrease the need for escalation of care, including the need for exchange transfusion, to prevent kernicterus 1. Early identification of infants without adequate response to phototherapy can lead to earlier escalation of care, potentially averting the need for an exchange transfusion and possibly preventing kernicterus 1. Discontinuing phototherapy as soon as it is safe reduces unnecessary exposure to phototherapy while minimizing the risk of rebound hyperbilirubinemia 1. Frequent measurement of TSB provides timely guidance regarding the efficacy of phototherapy and the possible need for an exchange transfusion 1. After discontinuation of phototherapy, a follow-up bilirubin level should be obtained within 12-24 hours to check for rebound hyperbilirubinemia, as recommended by the guidelines 1.

From the Research

Bilirubin Testing Frequency in Neonates Undergoing Phototherapy

• The frequency of bilirubin testing in neonates undergoing phototherapy for hyperbilirubinemia is not explicitly stated in the provided studies 2, 3, 4, 5, 6.
• However, the studies suggest that the timing and frequency of bilirubin testing may depend on various factors, such as the infant's gestational age, birth weight, and response to phototherapy 4, 5, 6.
• For example, a study on prophylactic phototherapy for preterm or low birth weight infants found that peak serum bilirubin levels were lower in the prophylactic phototherapy group, and the rate of exchange transfusion was reduced in one study with liberal transfusion criteria 4.
• Another study compared transcutaneous and serum bilirubin levels in term and late-preterm infants receiving phototherapy, and found that transcutaneous bilirubin measurements can be a reliable method for monitoring bilirubin levels and deciding when to discontinue phototherapy 5.
• A study on transcutaneous bilirubin levels in newborns <35 weeks' gestation found that transcutaneous bilirubin screening can identify infants who require a total serum bilirubin measurement to confirm or exclude the need for phototherapy 6.
• The American Academy of Pediatrics recommends that bilirubin levels be monitored closely in infants undergoing phototherapy, but does not specify a particular testing frequency 2, 3.