Ambient light exposure can cause transcutaneous bilirubinometer (TCB) readings to be inaccurate and may cause medical providers to underestimate jaundice severity in infants, according to a report recently published in Children.
Jaundice has myriad potential causes, including hemolytic disease of the fetus and newborn (HDFN), which causes red blood cells to rapidly break down, releasing a compound called bilirubin into the bloodstream. High levels of bilirubin may lead to jaundice, defined as yellowing of the skin, eyes and other tissues.
Total serum bilirubin (TSB), which can be measured through a blood test, is the standard for diagnosing neonatal jaundice. However, it may take several hours to analyze each sample and obtain results, causing strain on medical services and personnel. TCB is a tool used to quickly screen for neonatal jaundice by approximating bilirubin levels in the skin in just a few minutes.
In a previous study, the authors determined that TCB tends to underestimate jaundice severity compared to TSB. They found that areas with more light exposure, such as the forehead, tend to underestimate jaundice severity most, leading the authors to hypothesize that ambient light may contribute to the observed discrepancy between TCB and TSB readings.
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The study included 559 neonates at risk of neonatal jaundice. TCB measurements were obtained and compared with TSB measurements to evaluate variation between the two methods.
Findings revealed that TCB readings were lower than TSB levels for most participants, confirming the results of the prior study.
Furthermore, the discrepancy between TSB and forehead TCB readings was significantly smaller during the winter months than the spring and summer months, when exposure to ambient light tends to be higher. Notably, sternum TCB readings were not associated with season.
“Although we cannot prove that cumulative ambient light exposure causes the underestimation by TCB, we would like to caution pediatricians about this association when using TCB as the screening tool for outpatient [neonatal jaundice] management,” the authors concluded.
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