Nucleated red blood cell levels in the diagnosis of patients with indirect hyperbilirubinemia.

Background: Nucleated red blood cells (NRBCs) are progenitores of red blood cells that are physiologically seen in the peripheral blood of the fetus and newborn at birth. The increased numbers of NRBCs in the circulation is associated with pathologic conditions such as prematurity, hemolytic diseases and bleeding, intrauterine growth restriction. We aimed to evaluate the relationship between NRBCs and the demographic and clinical characteristics of the patients with indirect hyperbilirubinemia who were followed up in the neonatal intensive care unit.

Methods: In this retrospective study we evaluated 134 patients with indirect hyperbilirubinemia between January 2017 and December 2018. Patients were divided into two groups as those with ABO and/or Rh incompatibility and those without. Groups were compared in terms of demographic, clinical characteristics and for the hematological parameters.

Results: A total of 134 infants were evaluated in the study, including 68 (50%) infants with ABO incompatibility, 12 (8.9%) with Rh incompatibility and 3 (2.2%) with ABO and Rh incompatibility. Coombs test results were positive for 34 patients. There were no differences between ABO and/or Rh incompatibility group and non incompatibility group with regards to birth weight, gestational age and gender. In terms of hematologic parameters, there were no differences between the hemoglobin, hematocrit and mean platelet volumes of the patients at the time of hospitalization, while red cell distribution width, NRBCs per 100 white blood cells (NRBCs/100 WBCs) and absolute NRBC count were statistically higher in patients with ABO and/or Rh incompatibility. It was found that NRBCs/100 WBC and absolute NRBC count were statistically higher in patients with positive direct coombs test than patients with negative coombs test (p <0.05).

Conclusions: Early diagnosis of indirect hyperbilirubinemia is essential, as it can prevent to occur serious neurological sequelas. Elevated levels of NRBCs in infants with blood group incompatibilities could alert clinicians about the severity of jaundice and should increase awareness in terms of hemolysis.