Prothrombin Levels in Newborn Infants by the Carinactivase-1 Method

ABSTRACT

A recently developed method to quantitate prothrombin in plasma uses the carinactivase-1 (CA-1) method. The present study was designed to establish the reference value by the CA-1 method in the neonatal period and to explore the effect of gestational age, birth weight, concurrent diseases, and vitamin K administration on the prothrombin levels. We enrolled 78 consecutive neonates. The gestational ages ranged from 28 to 41 weeks, and the birth weight ranged from 850 to 3750 g. Twenty-nine infants had concurrent diseases, and the others (n = 49) were healthy. A 300 μL blood sample was drawn into a plastic syringe containing 60 U freeze-dried buffered heparin. Prothrombin levels did not differ between appropriate-for-date (AFD) and light-for-date (LFD) babies (p = 0.090) or between groups with and without concurrent diseases (p = 0.210). In healthy AFD babies, prothrombin levels correlated with gestational age (r = 0.465, p = 0.003) and birth weight (r = 0.458, p = 0.003). In healthy low-birth-weight infants (n = 14) and those with concurrent diseases (n = 17), the changes after vitamin K administration were not significant. The CA-1 method is of clinical use in monitoring coagulation during the early neonatal period.

KEYWORD

Prothrombin - newborn infants - vitamin K - carinactivase-1 method

REFERENCES

• 1 Yamada D, Morita T. CA-1 method, a novel assay for quantification of normal prothrombin using a Ca²⁺-dependent prothrombin activator, carinactivase-1.  Thromb Res . 1999;  94 221-226
• 2 Kudo T, Konagai N, Maeda M, Yano H, Ishimaru S. Anticoagulant therapy after cardiac valve replacement: the evaluation of the new CA-1 method of monitoring therapy.  Jpn J Artif Organ . 2000;  29 114-116
• 3 Andrew M. The relevance of developmental hemostasis to hemorrhagic disorders of newborns.  Semin Perinatol . 1997;  21 70-85
• 4 Peters M, Tencate W, Jansen E, Breederveld C. Coagulation and fibrinolytic factors in the first healthy infants.  J Pediatr . 1985;  106 292-295
• 5 Shima Y. Studies on prothrombin and factor IX in premature infants. 1. Prothrombin activity, prothrombin antigen, factor IX activity, and factor IX antigen in premature infants.  J Nara Med Ass . 1983;  34 805-814
• 6 Hathaway W E. Coagulation problems in the newborn infants.  Pediatr Clin Haematol . 1978;  7 85-109
• 7 Hurlet-Birk Jansen A, Jasso F, Zamet P, Monset-Couchard M, Minkowski A. Evolution of blood clotting factor levels in premature infants during the first 10 days of life: a study of 96 cases with comparison between clinical status and blood clotting factor levels.  Pediatr Res . 1973;  71 638
• 8 Cade J F, Hirsh J, Martin M. Placental barrier to coagulation factors: its relevance to the coagulation defect at birth and to haemorrhage in the newborn.  BMJ . 1969;  2 281
• 9 Shirakawa Y, Shirahata A, Fukuda M. Differences in reactivity to vitamin K administration of the vitamin K-dependent procoagulant factors, protein C and S, and osteocalcin.  Semin Thromb Hemost . 2000;  26 119-126