Transcutaneous bilirubin decision rules miss infants who will need phototherapy

Last Updated: 2016-04-07

By Reuters Staff

NEW YORK (Reuters Health) - All three of the recommended decision rules for "positive" transcutaneous bilirubin (TcB) measurements will fail to identify some infants with a total serum bilirubin (TSB) at or above the phototherapy threshold, researchers report.

TcB, a less invasive measure than TSB, aims to identify newborns with significant hyperbilirubinemia during their birth hospitalization. The American Academy of Pediatrics (AAP) has suggested three possible decision rules for TcB screening, and it is unclear which rule best identifies these neonates.

Dr. James A. Taylor, from the University of Washington, Seattle, and colleagues compared the utility of different decision rules for TcB screening in hopes of identifying at least one rule that would provide a false-negative rate near 0% in identifying newborns with a high TSB level, while eliminating the need for a blood draw in most infants.

They tested three decision rules: (1) TcB levels at least 75th percentile on the Bhutani TSB nomogram; (2) TcB levels above 70% of the TSB phototherapy threshold based on the AAP practice guideline; and (3) TcB levels greater than or equal to the AAP phototherapy threshold minus 3.0 mg/dL.

None of the decision rules identified all newborns with a TSB level above the phototherapy threshold -- the false-negative rates ranged from 3.2% for 70% of phototherapy level to 6.9% for at least 75th percentile to 9.7% for within 3 mg/dL, according to the April 6 Pediatrics online report.

The percentages of blood draws avoided were highest for within 3 mg/dL (83.8% and 90.7% for 2 sample populations), intermediate for 70% of phototherapy level (76.5% and 84.7%), and lowest for at least 75th percentile (67.2% and 79.4%).

"Because of the modest numbers of TSB levels above the phototherapy threshold in both samples, it is difficult to compare the utility of the different decision rules evaluated in this study," the researchers note. "However, our results suggest that the 70% of phototherapy level decision rule may be the most useful in a variety of clinical settings during the birth hospitalization in that it eliminates the need for more blood draws because of a false-positive screen than the (at least) 75th percentile rule while providing false-negative rates that are, at least, comparable to those of the other decision rules."

"Overall, perhaps the most striking finding of this study is that none of the three decision rules identified all newborns who had a TSB level above the phototherapy threshold or all newborns with a TSB level in the high-risk zone on the Bhutani nomogram," they conclude. "Thus, in a newborn whose jaundice appears on visual assessment to be more significant than indicated by a TcB measurement, a TSB level may still be warranted."

Dr. Taylor did not respond to a request for comments.

The National Institutes of Health funded this research. Two coauthors reported disclosures.

SOURCE: http://bit.ly/1SAKAum

Pediatrics 2016.