Value of the Direct Antiglobulin Test in Predicting the Need for Phototherapy in Newborns

Guidelines for managing neonatal hemolytic disease of the newborn (HDN) recommend a selective approach in the use of direct antiglobulin test (DAT). In Saudi Arabia, many hospitals still perform routine DAT for all newborns. This study assessed the need for phototherapy in relation to DAT results in full-term healthy newborns.

A retrospective analysis of all healthy newborns admitted during 2018 was performed. The primary outcome was the association of positive DAT results with phototherapy.

There were 1463 newborns born during the study period. The DAT was positive at 4.4%. The 24-hour bilirubin levels were higher in DAT-positive cases (P=0.06); however, peak bilirubin levels were not correlated with the DAT results (P=0.717). Thirty-six neonates (2.46%) required phototherapy, and the need was similar among DAT-positive and DAT-negative cases (P=0.271). The most common indication for phototherapy was clinical jaundice in 22 neonates (61.1%), followed by DAT positivity in 12 (33.3%) and hospital protocol in 2 patients (5.6%) (P <0.01 by chi-square overall comparison).

Our results indicate that factors other than DAT positivity are important in assessing the need for phototherapy in newborns. Clinical signs of jaundice were indicators of high serum bilirubin levels and subsequent phototherapy, further indicating that the DAT test was overused in predicting the need for phototherapy.