Current practice at our hospital is to perform a direct antiglobulin test (DAT) on cord blood samples of all infants born to blood type O or Rh-negative mothers. Measurement of serum total bilirubin (STB) level and follow-up after discharge are at the discretion of the individual physician. The purposes of the present study were, first, to determine the clinical utility of performing a routine DAT and, second, to define the clinical characteristics of infants readmitted to the hospital for phototherapy. The study was done over a 1-year period extending from January 1 to December 31, 2000. A retrospective review of the DAT results of all infants born to type O or Rh-negative mothers was conducted. The 2 groups of infants included those who had a positive cord blood DAT and were treated with phototherapy and those who needed readmission to the hospital for phototherapy. We found that routine DAT testing of cord blood from term nonjaundiced infants born to O positive mothers is not necessary. Infants with 2 or more risk factors for jaundice irrespective of the results of the DAT are at an increased risk for needing readmission for phototherapy.