Routine blood typing and DAT in infants of group O mothers

Sixth-Hour Trancutaneous Bilirubin and Need for Phototherapy in DAT Positive Newborns

OBJECTIVES

To characterize the outcomes of ABO incompatible direct antiglobulin test (DAT) positive newborns and determine the predictive ability of a sixth-hour transcutaneous bilirubin (TcB for needing phototherapy ≤24 hours of age.

METHODS

Retrospective, cross-sectional study from May 2013 to March 2017. Of 10 942 consecutive newborns ≥35 weeks estimated gestational age, 829 were ABO incompatible and DAT positive. After excluding for antibodies other than ABO (51), missing data (4), miscategorization of blood type O (1), and duplicate record (1), 772 newborns remained. Of 772, a subsample of 346 newborns with both TcB and total serum bilirubin (TSB) tests within 1 hour of the sixth hour was analyzed to determine the predictive ability.

RESULTS

Phototherapy was required in 281 of 772 (36.4%); 156 (20.2%) in the first 24 hours. There were 10 (1.3%) admissions for hyperbilirubinemia to the NICU for intravenous immunoglobin. Birth weight, infant blood type B, TSB, reticulocyte count, and TcB were all significantly associated with phototherapy ≤24 hours. On multivariate analysis, significant predictors of phototherapy ≤24 hours were TSB and reticulocyte count if no TcB was done and TcB alone if no blood tests were done. TcB was highly predictive (odds ratio 3.1, 95% confidence interval: 2.4-4.0) and nearly as accurate as the TSB and reticulocyte count (area under the curve, 0.90 and 0.96, respectively). Low (<3.0 mg/dL) and high (≥5.3 mg/dL) risk TcB cutoffs demonstrated a negative predictive value of 98% and positive predictive value of 85%, respectively.

CONCLUSIONS

Among high-risk ABO incompatible DAT positive newborns, the sixth-hour TcB is highly predictive of the need for phototherapy ≤24 hours.

Survey of newborn direct antiglobulin testing practice in United States and Canadian transfusion services

BACKGROUND

We hypothesized that variability in practice exists for newborn immunohematology testing due to lack of consensus guidelines. We report the results of a survey assessing that variability at hospitals in the United States and Canada.

STUDY DESIGN AND METHODS

An AABB Pediatric Subsection working party developed and validated a survey of newborn immunohematology testing practice. The survey was sent electronically to transfusion service leadership at teaching institutions.

RESULTS

The response rate was 67% (61/91); 56 surveys meeting inclusion criteria were analyzed. Approximately 90% (50/56) were from birth hospitals and 16.1% (9/56) were from pediatric hospitals. Newborn immunohematology testing is ordered as a panel by 66.0% (33/50) of birth hospitals. ABO group and DAT is mandated before discharge in 14/56 (25.0%) and 13/56 (23.2%), respectively. About 76.8% (43/56) selectively perform a DAT according to blood blank or clinical parameters. The most common DAT practices include anti-IgG only testing by 73.2% (41/56) and use of umbilical cord specimen type by 67.9% (38/56). A positive DAT is a critical value for 26.8% (15/56) and followed with eluate testing when a maternal antibody screen is positive for 48.2% (27/56). In the setting of a non-ABO maternal red cell antibody, 55.4% (31/56), phenotype neonatal red cells when the DAT is positive. Group O RBC are transfused irrespective of the DAT result for 82.1%, (46/56).

CONCLUSION

There is variability in newborn immunohematology testing and transfusion practice and potential overutilization of the DAT. Evidence-based consensus guidelines should be developed to standardize practice and to improve safety.

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

Purpose

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.

Patients and Methods

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

Results

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).

Conclusion

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.

ABO hemolytic disease of the fetus and newborn: thirteen years of data after implementing a universal bilirubin screening and management program

OBJECTIVE

ABO hemolytic disease occurs among neonates with blood groups A or B delivered to group O women. Extreme neonatal hyperbilirubinemia due to ABO disease has been reported, but its frequency is not well known. We sought to determine the odds of developing severe ABO hemolytic disease in the 13 years since adopting universal bilirubin screening/management in the Intermountain Healthcare system.

STUDY DESIGN

We conducted a retrospective analysis of neonates born between 2004 and 2016, defining "severe hemolytic disease" as; (1) total serum bilirubin (TSB) >25 mg/dL, or (2) hospital readmission for jaundice, or (3) bilirubin encephalopathy. Neonates born to group O (+) mothers were included and considered either; (1) Controls (not at risk for ABO disease because they were group O), (2) Study subjects (at risk for ABO disease because they were group A or B).

RESULTS

Of 400,531 live births, 47% were to group O women; 86% of whom were group O (+). Overall, 42,529 (27%) neonates born to group O (+) women had their blood group determined; 29,729 (68%) were O, 10,682 (25%) A, and 3109 (7%) B. Peak TSBs during the first 10 days were higher in group A (11.0 ± 4.2 mg/dL) and B (11.5 ± 4.3) than group O neonates (10.3 ± 4.1). However the relative risks of a TSB ≥25 mg/dL, readmission for jaundice, or kernicterus, were the same in the control vs. study groups.

CONCLUSIONS

In our health system, severe hemolytic disease in neonates born to group O (+) woman is not more likely in group A or B neonates than in controls (group O). We recognize that in other practices, particularly those who do not have a universal bilirubin screening/management program, ABO hemolytic disease severity might be different than in our system.

How to use: the direct antiglobulin test in newborns

The direct antiglobulin test (DAT) detects the presence of immunoglobulin, complement or both bound to the red blood cell membrane. The test, historically called the 'Coombs test', was first described in 1945 by Cambridge immunologist Robin Coombs. Suspected haemolytic disease of the newborn, due to either Rhesus disease or ABO incompatibility, is one of most common reasons for requesting a DAT in newborns. In this article, we discuss the physiological background and technological background of the DAT. We also provide a clinical framework for a rational approach to the use and interpretation of the DAT in newborns.

Common hematologic problems in the newborn nursery

"Common red blood cell disorders encountered in the normal newborn nursery include hemolytic disease of the newborn and resultant hyperbilirubinemia, anemia, and polycythemia. A less frequent clinically relevant hematologic issue in newborns to be covered herein is thrombocytopenia."