ASSESSMENT OF VITAMIN-K STATUS OF THE NEWBORN-INFANT

This article reviews our current knowledge of the assessment of vitami n K status in the human infant, where a deficiency state has been desc ribed. Laboratory measures for the functional assessment of vitamin K- dependent coagulation factors as well as the quantitative assay for vi tamin K1 (phylloquinone) are reviewed. In addition, four different met hods of measuring abnormal prothrombin, a protein induced by vitamin K absence (PIVKA-II), and its use in clinical pediatrics are discussed. Finally, additional methods are briefly described for assessing vitam in K status, including serum osteocalcin, urinary excretion of gamma-c arboxyglutamic acid, and deficiencies of the enzymes necessary for the regeneration of phylloquinone in the so-called vitamin K cycle.