General blood test: reference values for full-term and late preterm newborns in the first day of life (Part 2)

Development of reference values for both absolute and relative blood levels of various types of leukocytes as well as the neutrophil index (NI) in both the conditionally “healthy” full-term and the late premature newborns (LPN) is primarily aimed at determining the standards obtained using modern laboratory technologies that would be of help in recognizing hematological disorders in the early neonatal period. This is the continuation of the research with its initial results previously published in the Journal “Pediatria. Journal named after G.N. Speransky” in 2022, i.e.: A.L. Karpova. Complete blood count: reference intervals for full-term and late premature infants in the first day of life (part I). Pediatria n.a. G.N. Speransky. 2022; 101 (1): 62-70. DOI: 10.24110/0031-403X-2022-101-1-62-70. https://doi.org/10.24110/0031-403X-2022-101-1-62-70. The purpose of the research was to determine and compare the general blood test (GBT) reference values in full-term infants and LPN who did not require intensive care and stayed at the obstetrics/physiological departments during the first day of life in order to use them as normative indicators in clinical practice. Materials and methods used: multicenter prospective cohort study was conducted in 2019-2020: 4,376 full-term infants and LPN were examined. Inclusion criteria: 1) the first minute APGAR score of 7 points or above; 2) aged 18 to 24 hours of life; 3) absence of diseases in newborns by the end of the first day of life; 4) gestational age at birth of 35 0/7 to 41 6/7 weeks. In order to avoid errors in obtaining the reference values for white blood cell counts depending on the gestational age (GA), only those children whose GA was specified more precisely, and not as a range - e.g., “37 to 38 weeks,” were included in the analysis. As a result, 3,334 newborns were selected and divided into 2 comparison groups: G1 (n=3,225) of full-term newborns and G2 (n=109) of LPN. Results: reference values of absolute and relative content of different types of leukocytes, leukocytes, lymphocytes, monocytes are presented as tables and nomograms depending on GA. When comparing the GBT parameters, statistically significant differences were found between full-term infants and LPN in the absolute number of segmented neutrophils (13.5 [0.7-44.3] v. 10.1 [3.6-22.0], p<0.001); lymphocytes (5.3 [0.0-25.7] v. 4.7 [2.2-9.5], p<0.001); monocytes (2.1 [0.0-9.1] v. 1.5 [0.2-4.3], p<0.001); eosinophils (0.4 [0.0-4.6] v. 0.2 [0.0-1.4], p<0.001) and basophils (0.0 [0.0-0.3] v. 0.0 [0.0-0.3], p<0.001), which were statistically significantly lower in LPN than in full-term newborns. Conclusion: the absolute number of segmented neutrophils, lymphocytes, monocytes, eosinophils and basophils in the blood of LPN in the first 24 hours of life is lower compared to those of full-term infants.