From the Guidelines
Monitoring parameters for a DAT-positive newborn should include frequent total serum bilirubin (TSB) measurements, as well as assessment of the rate of rise of TSB levels, to guide the need for phototherapy or other interventions. According to the most recent guidelines 1, TSB should be used as the definitive diagnostic test to guide all interventions, and it should be measured if the transcutaneous bilirubin (TcB) reading is within 3.0 mg/dL of the phototherapy treatment threshold, if the TcB exceeds the phototherapy treatment threshold, or if the TcB is ≥15 mg/dL.
Key Monitoring Parameters
- Frequent TSB measurements to assess the need for phototherapy or exchange transfusion
- Assessment of the rate of rise of TSB levels to identify possible hemolysis
- Clinical assessment for signs of hemolysis and anemia
- Monitoring for signs of kernicterus, including lethargy, poor feeding, high-pitched cry, and abnormal muscle tone
- Regular assessment of vital signs, including heart rate, respiratory rate, and temperature
Frequency of Monitoring
The frequency of monitoring can be decreased as bilirubin levels stabilize or decline, but close follow-up after discharge is essential, typically within 24-48 hours, as bilirubin levels may continue to rise 1. Infants who received phototherapy <48 hours of age, with a gestational age <38 weeks, with a positive direct antiglobulin test (DAT), or suspected of having hemolytic disease should have a follow-up TSB measure 8 to 12 hours after phototherapy discontinuation and on the following day.
Importance of Monitoring
This intensive monitoring is necessary because DAT-positive newborns are at higher risk for hemolytic disease, which can lead to severe hyperbilirubinemia and potentially kernicterus if not promptly identified and treated 1. The positive DAT indicates antibody-coated red blood cells that are prone to destruction, making these infants particularly vulnerable to rapid bilirubin elevation.
From the Research
Monitoring Parameters for DAT Positive Newborns
The following parameters are necessary for monitoring DAT positive newborns:
- Hemoglobin (Hb) level: DAT strength was found to be significantly associated with Hb level 2
- Bilirubin level: Total bilirubin levels should be monitored, as they can range broadly between 0.2 and 14.3 mg/dL 3
- Direct bilirubin level: Direct bilirubin level was higher in infants with positive DAT 4
- Reticulocyte count: Reticulocyte ratios can indicate the effectiveness of hematopoiesis, which may be suppressed in fetuses with maternal anti-Jra 3
- Phototherapy: Infants with positive DAT may require phototherapy, and the duration of hospitalization may be longer 4
Clinical Considerations
- ABO incompatibility: ABO blood group incompatibility is a common cause of neonatal indirect hyperbilirubinemia, and a positive DAT can identify infants developing hemolytic disease 4
- Hemolytic disease of the newborn (HDN): HDN can cause fetal hydrops during pregnancy or neonatal jaundice after birth, and a positive DAT can aid in the diagnosis of HDN 5
- Exchange transfusion: In severe cases of HDN, exchange transfusion may be necessary 5, 6
Laboratory Tests
- Direct Antiglobulin Test (DAT): DAT can detect antibodies bound to red cells and is a valuable test aiding in the diagnosis of HDN 2, 5, 6, 3, 4
- Elution tests: Elution tests can aid in the diagnosis of DAT-negative ABO-incompatible hemolytic anemia 2
- Antibody screening and identification: These tests can help identify the underlying cause of HDN and guide treatment 2