title: Importance of Direct Antiglobulin Test (DAT) in Cord Blood: Causes of DAT (+) in a Cohort Study.
abstract: BACKGROUND
  The direct antiglobulin test (DAT) is the cornerstone of the diagnosis of hemolytic disease of the newborn (HDN). The aim of this study was to review the incidence and causes of positive DAT in cord blood in relation to development of HDN.
  
  
  METHODS
  We retrospectively reviewed all results of DAT, which is routinely performed in cord blood samples, along with the laboratory and infants' medical records.
  
  
  RESULTS
  DAT was positive in 70/2695 (2.59%) cases. In 64/70 (91.43%) cases, DAT positivity was attributed to ABO incompatibility. There were 50/218 (22.93%) DAT (+) cases in the A/O group and 13/97 (13.40%) cases in the B/O group (p = 0.0664). Two DAT (+) cases were attributed to maternal alloimmunization (anti-Fya and anti-JKb, respectively), and one to maternal IgG autoantibodies that developed after methyldopa treatment. Among the 70 DAT (+) cases, 30 (42.86%) cases required phototherapy with no difference between the A/O and B/O groups. The duration of phototherapy in the B/O group was significantly longer than in the A/O group (p = 0.024). There was a trend of correlation of increasing strength of DAT positivity with phototherapy need. No false positive DAT case was detected.
  
  
  CONCLUSIONS
  Although ABO incompatibility remains the main reason of DAT (+), other causes (e.g., alloimmunization, drugs) should also be explored. The relevant impact of DAT (+) on HDN development should be considered.
authors: Blood Transfusion Department, Aretaieion Hospital, Athens University Medical School, Athens, Greece. Electronic address: serenavalsami@yahoo.com.
authors: Serena
authors: S
authors: Valsami
authors: Blood Transfusion Department, Aretaieion Hospital, Athens University Medical School, Athens, Greece.
authors: Marianna
authors: M
authors: Politou
authors: Neonatal Division, 2nd Department of Obstetrics and Gynecology, Aretaieion Hospital, Athens University, Medical School, Athens, Greece.
authors: Τheodora
authors: Τ
authors: Boutsikou
authors: Neonatal Division, 2nd Department of Obstetrics and Gynecology, Aretaieion Hospital, Athens University, Medical School, Athens, Greece.
authors: Despina
authors: D
authors: Briana
authors: Neonatal Division, 2nd Department of Obstetrics and Gynecology, Aretaieion Hospital, Athens University, Medical School, Athens, Greece.
authors: Milena
authors: M
authors: Papatesta
authors: Neonatal Division, 2nd Department of Obstetrics and Gynecology, Aretaieion Hospital, Athens University, Medical School, Athens, Greece.
authors: Ariadne
authors: A
authors: Malamitsi-Puchner
mesh_terms: D000017:ABO Blood-Group System / Q000276:immunology*; D001787:Blood Group Incompatibility / Q000276:immunology*; D015331:Cohort Studies; D003298:Coombs Test / Q000379:methods*; D004899:Erythroblastosis, Fetal / Q000175:diagnosis* / Q000276:immunology; D005260:Female; D005312:Fetal Blood; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D010789:Phototherapy; D012189:Retrospective Studies
chemical_list: D000017:ABO Blood-Group System
keywords: ABO incompatibility; direct antiglobulin test (DAT); hyperbilirubinemia; maternal alloimmunization; phototherapy