Most Proper Timing of Transcutaneous Bilirubin Measurement After Phototherapy Treatment in the Newborn Period

Background: There are limited data about the proper transcutaneous bilirubin measuring time to detect levels that are close to serum bilirubin levels after ending the phototherapy treatment. Objectives: To compare the transcutaneous bilirubin and total serum bilirubin levels, and to evaluate the reliability of transcutaneous bilirubin measurements after phototherapy treatment of newborns because of hyperbilirubinemia. Methods: The study included 105 late preterm and term newborns consisting of 56 females (53.3%) and 49 males (46.6%), with gestational age 35(0/7)-41(6/7) weeks who were treated with phototherapy. A Bilicheck (M&B-MBJ20) device was used for transcutaneous bilirubin measurements. The average of three measurements on the skin in the mid-sternal area were obtained. Correlations between transcutaneous bilirubin and venous bilirubin levels were evaluated 6 and 12 hours after phototherapy. Transcutaneous bilirubin measurements were performed simultaneously with blood collection or within a maximum +/- 15 minutes time difference for total serum bilirubin. Results: The average phototherapy time was 10 +/- 2 (range, 8 - 12) hours. The average difference between transcutaneous bilirubin and venous bilirubin levels post phototherapy was 2.61 mg/dL after 6 hours and 0.8 mg/dL after 12 hours. The hematocrit levels of the patients ranged between 40 - 66% with an average of 53% +/- 4.8, the median level was 51%. Correlation coefficients according to hours after treatment were high for the 6th hour (r = 0.76) and very high for the 12th hour. Conclusions: Jaundice scanning with transcutaneous bilirubin measurements 6 -12 hours after the end of phototherapy is reliable and may be helpful in preventing additional blood collection from the heel.