Blood Type Testing and Management in Newborns

Key Indications for Blood Type Testing

Testing for ABO and Rh (D) blood types in newborns helps identify potential hemolytic disease of the newborn (HDN), which can cause anemia, hyperbilirubinemia, and in severe cases, kernicterus or death, as recommended by the American Academy of Pediatrics 1, 2
When maternal blood is group O and Rh-positive, testing the cord blood for the infant's blood type and direct antibody test is optional but recommended for appropriate surveillance and follow-up, according to the American Academy of Pediatrics 1
For Rh-negative mothers, cord blood testing for the infant's blood type and direct antibody test (Coombs' test) is strongly recommended to identify potential Rh incompatibility, as suggested by the American Academy of Pediatrics 1

The direct antiglobulin test (DAT or direct Coombs' test) on newborn blood samples is used to detect antibody-coated red blood cells, suggesting immune-mediated hemolysis, with a strength of evidence level of moderate to high 3, 4
In cases of suspected hemolytic disease, additional laboratory tests include total serum bilirubin, complete blood count with reticulocyte count, and blood smear for red cell morphology, as recommended by the American Academy of Pediatrics 5

Severe cases of hemolytic disease may require intensive phototherapy, intravenous immunoglobulin, or exchange transfusion if bilirubin levels approach or exceed exchange transfusion thresholds, with a high strength of evidence 5, 6
The risk of kernicterus increases significantly when total serum bilirubin exceeds 25 mg/dL (428 μmol/L), making early identification of at-risk infants through blood typing critical, according to the American Academy of Pediatrics 5

For known cases of maternal sensitization, antenatal monitoring with middle cerebral artery Doppler studies may be indicated when antibody titers reach critical levels, as suggested by the American College of Obstetricians and Gynecologists 3

The American Academy of Pediatrics recommends using intensive phototherapy with special blue fluorescent tubes or LED light sources delivering spectral irradiance >30 μW/cm²/nm in the blue-green spectrum (425-475 nm) to treat neonatal jaundice 7
Positioning lights 10-15 cm above the infant and exposing maximum body surface area by placing lights above and fiber-optic pads below the infant is recommended to maximize irradiance 7
Lining the sides of the bassinet or incubator with aluminum foil can increase reflected light exposure and enhance the effectiveness of phototherapy 7
Higher bilirubin levels (>20 mg/dL or 342 μmol/L) will show more rapid decline with intensive phototherapy 7

The treatment algorithm for neonatal jaundice due to ABO and Rh incompatibility involves starting intensive phototherapy immediately with spectral irradiance >30 μW/cm²/nm, maximum surface area exposure 7