Transcutaneous bilirubin levels in newborns <35 weeks' gestation

Area of Science:

• Neonatal Medicine
• Pediatric Gastroenterology
• Clinical Chemistry

Background:

• Hyperbilirubinemia is common in preterm infants.
• Total serum bilirubin (TSB) tests guide phototherapy decisions.
• Transcutaneous bilirubin (TcB) measurements offer a non-invasive alternative.

Purpose of the Study:

• To determine TcB levels that reliably predict when TSB testing is unnecessary for preterm infants (<35 weeks gestation).
• To establish criteria for avoiding TSB measurements, reducing invasive procedures.

Main Methods:

• 896 TcB and TSB measurements were taken within 1 hour of each other in 225 neonates (26-34 weeks PMA).
• Generalized estimating equations (GEEs) modeled the probability of TSB reaching phototherapy thresholds based on TcB values.
• Data were analyzed across different postmenstrual age (PMA) categories.

Main Results:

• Mean TcB-TSB difference was <1 mg/dL across PMA groups.
• A TcB at least 3 mg/dL below the phototherapy cutpoint yielded a ≥98% probability that TSB was below the treatment level.
• An exception was noted for 28-29 week infants, requiring a TcB ≥4 mg/dL below the threshold.

Conclusions:

• Routine TcB screening is supported for infants 28-34 6/7 weeks gestation.
• TcB screening effectively identifies neonates who do not require TSB confirmation for phototherapy.
• This non-invasive method can optimize care in the neonatal intensive care unit.