The Diagnostic Significance of the Reticulated Platelet in Thrombocytopenia of Newborn, Prematurity and Perinatal Asphyxia

Kim, Hwang Min; Park, Song Hee; Lim, Baek Keun; Lee, Chang Hoon

Abstract

BACKGROUND: Reticulated platelets(RPs) are young platelets with high RNA content. The RP percentage(RPP) reflects bone marrow thrombopoietic activity. The aim of this study is to determine the normal value of RPPs in fullterm and premature neonates at birth and at 7 days of age, and to find out the diagnostic significance of RPP in thrombocytopenic neonates of various causes.
METHODS
Flow cytometric measurements of RPP were performed in 38 healthy fullterm(Group 1), 30 premature(Group 2), 15 healthy, spontaneously recovered thrombocytopenic neonates(Group 3), 21 neonates with thrombocytopenia due to sepsis, perinatal asphyxia or hyaline membrane disease(HMD)(Group 4), and 25 healthy adults(Group 5).
RESULTS
The RPPs of groups 1 and 2 were 3.10+/-2.00%(mean+/-SD) and 3.80+/-2.96% at birth, 2.66+/-1.44% and 2.85+/-1.69% at 7 days of age respectively. That of group 5 was 7.17+/-2.01%. Normal RPPs of healthy term and preterm neonates were significantly lower than that of healthy adults. The RPPs of term groups 3 and 4 were 2.05+/-2.43% and 6.94+/-3.66% respectively. That of preterm groups 3 and 4 were 2.00+/-1.04% and 7.29+/-4.87% respectively. The RPP of group 4 was significantly higher than groups 1, 2, or 3. There was no significant difference of Mean Platelet Volume(MPV) or Platelet Distribution Width(PDW) between group 3 and group 4. Reasonable cut-off value of RPP for the diagnosis of Group 4 was 8%, by which we could confirm 9 cases among 21 cases of neonatal thrombocytopenia due to sepsis, perinatal asphyxia, or hyaline membrane disease.
CONCLUSIONS
The bone marrow thrombopoietic activity of neonates seems to be lower than that of adults. Decreased thrombopietic activity of bone marrow seems to be a cause of spontaneously recovering idiopathic neonatal thrombocytopenia. Increased platelet destruction seems to be a cause of neonatal thrombocytopenia due to sepsis, perinatal asphyxia, or hyaline membrane disease. The RPP higher than 8% could be a good supportive diagnostic criterion for neonatal thrombocytopenia due to sepsis, perinatal asphyxia, or hyaline membrane disease.