A-393 Evaluating Discrepancies in Transcutaneous Bilirubin Measurements: The Impact of Skin Tone and Device Precision on Neonatal Jaundice Screening

Abstract Background Dräger Jaundice Meter JM-105 is a transcutaneous bilirubin (TcB) meter utilized to screen neonates for jaundice in Saskatoon, Saskatchewan Canada. Elevated TcB readings are followed up with core laboratory testing of total serum bilirubin (TSB), and patients with high TSB levels undergo further evaluation with bilirubin fractionation to determine appropriate management. Failure to accurately identify and treat neonatal jaundice can lead to severe complications, including kernicterus. One important limitation of TcB meters is their lack of traditional quality assurance components, including quality control and proficiency testing materials. Concerns have been raised regarding discrepancies between TcB meter readings and core laboratory bilirubin results, as these inconsistencies may lead to unnecessary blood draws in patients with falsely elevated TcB levels or, more critically, missed diagnoses in patients with falsely low TcB readings. This study aims to identify possible sources of these discrepancies. Methods Between 2023 and 2025, TcB measurements were taken from 235 neonates as part of the post-calibration workup of a fleet of Dräger Jaundice JM-105 meters during routine screening. Five replicates were taken per patient, and the average reading was calculated and compared to time-matched TSB levels, which were measured using the Roche Cobas® c502 (Bilirbin Total Gen. 3). Concordance was assessed by how many TcB-TSB pairs exceeded a total allowable error (TEa) of 15-20% for TSB. The precision of replicate readings was also assessed and compared against manufacturer’s specifications, which state that readings should be within 50 µmol/L. Neonates were classified as having light, medium, or dark skin tone using color swatches. For each meter, ten consecutive electronic light checks were performed daily for five days, and the percent coefficient of variance was calculated. An acceptance goal of 10% was set for light checks based on consultation with other laboratories using the Dräger Jaundice JM-105 meters. Results Of the matched TcB-TSB pairs, 28.1% (66/235) exceeded a TEa of 15%, 16.6% (41/235) exceeded 20%, and 6.3% (15/235) surpassed 30%. Skin tone was found to influence TcB accuracy, with 90.0% (9/10) of patients with darker skin exhibiting TcB overreads. Overreads were also observed in 15.0% (16/107) of light-skinned and 20.3% (22/108) of medium-skinned neonates beyond the 15% TEa threshold. Falsely low TcB readings were identified in 7.5% (8/107) of light-skinned neonates and 3.7% of medium-skinned neonates; no falsely low readings were observed in dark-skinned neonates. Overall, 6% (14/235) of replicate readings exceeded the manufacturer’s specification, with some variations exceeding 100 µmol/L. Additionally, 38% of electronic light checks failed to meet the laboratory*s precision goal of 10%. Conclusion At least some of the discrepant TcB readings can be attributed to the skin tone of the patient. However, imprecise readings, whether due to user technique or device limitations, cannot be ruled out. These issues highlight the critical need for continuous quality assurance measures and the development of validated QC materials to enhance the reliability of TcB measurements. Addressing these challenges is crucial for improving the accuracy of neonatal jaundice screening and ensuring better patient outcomes.