From the Guidelines
For newborns with an initially elevated bilirubin level, you should recheck the total serum bilirubin (TSB) level. The timing of repeat measurements depends on the initial bilirubin value, the infant's age in hours, and risk factors present, as outlined in the technical report on phototherapy to prevent severe neonatal hyperbilirubinemia 1. Generally, follow-up should occur within a timeframe guided by the TSB trajectory and infant age. Transcutaneous bilirubin (TcB) measurements can be used for screening, but once levels approach treatment thresholds, confirmation with TSB is recommended, especially if the TcB reading is within 3.0 mg/dL of the phototherapy treatment threshold, exceeds the phototherapy treatment threshold, or is ≥15 mg/dL 1.
For infants receiving phototherapy, bilirubin should be rechecked to verify efficacy after starting phototherapy, with the timing guided by the TSB trajectory and infant age 1. After discontinuing phototherapy, a follow-up TSB should be obtained, with the exact timing depending on the infant's risk factors and the duration of phototherapy, such as within 8 to 12 hours after phototherapy discontinuation for certain high-risk groups 1. The decision to use TSB or TcB for follow-up measurements after phototherapy discontinuation should consider the time elapsed since phototherapy was stopped, with TcB being an option if it has been ≥24 hours since phototherapy was stopped 1.
Key considerations in the management of newborns with elevated bilirubin levels include:
- The use of TSB as the definitive diagnostic test to guide interventions 1
- The measurement of TSB to verify efficacy after starting phototherapy and to guide the discontinuation of phototherapy 1
- The evaluation of the underlying cause of hyperbilirubinemia, particularly in infants who require phototherapy or have a sudden rise in TSB levels 1
- The monitoring for rebound hyperbilirubinemia after phototherapy discontinuation, with follow-up TSB measurements as needed 1
From the Research
Bilirubin Recheck in Newborns
- If the initial bilirubin level is elevated in newborns, it is essential to recheck the total serum bilirubin level to assess the need for further treatment or intervention 2, 3.
- The American Academy of Pediatrics recommends using nomograms to plot total serum bilirubin levels and taking into consideration hyperbilirubinemia and neurotoxicity risk factors to determine the need for phototherapy or exchange transfusion 3.
- The type of bilirubin to recheck is typically the total serum bilirubin level, which includes both conjugated and unconjugated bilirubin 4, 5.
- Transcutaneous bilirubin measuring devices can also be used to estimate the bilirubin level, but a serum bilirubin test may be necessary to confirm the results 5.
- It is crucial to consider the gestational age and risk factors of the newborn when interpreting the bilirubin level and determining the need for treatment 2, 6.