Copyright 2016 American Medical Association. All rights reserved. Association Between Laboratory Calibration of a Serum Bilirubin Assay, Neonatal Bilirubin Levels, and Phototherapy Use Michael W. Kuzniewicz, MD, MPH; Dina N. Greene, PhD; Eileen M. Walsh, RN, MPH; Charles E. McCulloch, PhD; Thomas B. Newman, MD, MPH IMPORTANCE The American Academy of Pediatrics treatment recommendations for neonatal jaundice are based on age-specific total serum bilirubin (TSB) levels. In May 2012, Ortho Clinical Diagnostics adjusted the calibrator values for Vitros Chemistry Products BuBc Slides (Ortho Clinical Diagnostics), a widely used method to quantify TSB, after concerns of positively biased results. OBJECTIVE To investigate the association between recalibration of a reflectance spectrophotometry serum bilirubin assay and TSB levels and phototherapy use among newborns. DESIGN, SETTING, AND PARTICIPANTS Descriptive study comparing TSB levels and phototherapy use before and after recalibration at Kaiser Permanente Northern California, a large, integrated health care delivery system. The study evaluated live births at or after 35 weeks’ gestation at 12 facilities that used universal serum bilirubin screening before (January 1, 2010, through April 30, 2012; n = 61 677) and after (July 1, 2012, through December 31, 2013; n = 42 571) recalibration. The analysis took place in December 2015. INTERVENTION Recalibration of bilirubin testing instruments. MAIN OUTCOMES AND MEASURES Proportions of newborns with (1) at least 1 TSB value at or above 15 mg/dL; (2) at least 1 TSB level exceeding the American Academy of Pediatrics phototherapy threshold; (3) phototherapy during the birth hospitalization; and (4) at least 1 readmission for phototherapy. RESULTS In 104 420 infants (61 677 in the prerecalibration period and 42 511 in the postrecalibration period), a TSB was obtained in 99.2% of infants during birth and in 99.5% of infants within the first 30 days after birth. The postrecalibration period was associated with a 1.25 mg/dL (95% CI, 1.19-1.31; P < .001) decrease in mean maximum TSB, which led to a 39% relative reduction (from 20.4% to 12.4%) in infants with a TSB level of 15 mg/dL or more and a 51% relative reduction (from 9.3% to 4.5%) in infants with a TSB level that was at or above the American Academy of Pediatrics phototherapy threshold. Phototherapy during birth hospitalizations was reduced by 59% (absolute risk reduction, 5.5%; 95% CI, 4.7%-6.1%) and readmissions for phototherapy by 53% (absolute risk reduction, 1.8%; 95% CI, 1.4%-2.3%). CONCLUSIONS AND RELEVANCE Modest recalibration-induced reductions in mean TSB concentrations was associated with a significant reduction in the percentage of infants with clinically significant hyperbilirubinemia. Current laboratory accuracy standards are insufficient to detect biases that can have significant clinical effect. These data underline the need for increased integration of laboratory expertise into clinical guidelines and to support international initiatives to standardize laboratory measurements. JAMA Pediatr. 2016;170(6):557-561. doi:10.1001/jamapediatrics.2015.4944 Published online April 11, 2016. Editorial page 529 Journal Club Slides at jamapediatrics.com CME Quiz at jamanetworkcme.com and CME Questions page 627 Author Affiliations: Division of Research, Kaiser Permanente Northern California, Oakland (Kuzniewicz, Walsh, Newman); Division of Neonatology, Kaiser Permanente Northern California, Oakland, California (Kuzniewicz); Department of Pediatrics, University of California, San Francisco (Kuzniewicz, Newman); Department of Laboratory Medicine, University of Washington, Seattle (Greene); Department of Epidemiology and Biostatistics, University of California, San Francisco (McCulloch, Newman). Corresponding Author: Michael W. Kuzniewicz, MD, MPH, Division of Research, Kaiser Permanente Northern California, 2000 Broadway Ave, Oakland, CA 94612 (michael.w.kuzniewicz@kp.org). Research Original Investigation (Reprinted) 557 Copyright 2016 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 06/06/2020