title: PIVKA-II correlates with INR but not protein C or protein S concentrations in cord blood among newborns.
abstract: BACKGROUND
  Protein induced by vitamin K absence (PIVKA)-II, inactive precursor of prothrombin, is elevated in vitamin K (VK) deficiency. Our aims were to find the prevalence of VK deficiency in neonates, assess the utility of international normalized ratio (INR) as a screening tool, and explore the relationship between PIVKA-II, activated partial thromboplastin time (aPTT) and VK dependent anticoagulants.
  
  
  METHODS
  INR, aPTT, PIVKA-II, and proteins C and S activities were measured in neonatal cord blood prior to VK administration.
  
  
  RESULTS
  We found 45% of neonates had subclinical VK deficiency based on PIVKA-II levels and 7% based on INR. Receiver operating characteristic (ROC) analysis assessed the utility of INR in detecting >4 ng/mL of PIVKA-II and ROC of the area under the curve was 0.70 (95% CI 0.46-0.92, p = 0.07). Proteins C and S activities were normal for age and did not correlate with PIVKA-II [(r = 0.40, p = 0.14) and (r = 0.29, p = 0.29), respectively]. There was no association between aPTT and PIVKA-II (p = 0.83).
  
  
  CONCLUSIONS
  PIVKA-II seems to be a sensitive indicator of mild VK deficiency. Further studies are needed to investigate the lack of relationship between PIVKA-II and functional protein C or S levels.
authors.affiliation: Baylor College of Medicine, Houston, TX, USA.
authors.forename: M
authors.initials: M
authors.lastname: Teruya
authors.affiliation: Baylor College of Medicine, Houston, TX, USA.
authors.forename: E
authors.initials: E
authors.lastname: Soundar
authors.affiliation: Baylor College of Medicine, Houston, TX, USA.|Texas Children's Hospital, Houston, TX, USA.
authors.forename: S R
authors.initials: SR
authors.lastname: Hui
authors.affiliation: Baylor College of Medicine, Houston, TX, USA.|Texas Children's Hospital, Houston, TX, USA.
authors.forename: K
authors.initials: K
authors.lastname: Eldin
authors.affiliation: Esoterix Coagulation, Laboratory Corporation of America Holdings, Englewood, CO, USA.
authors.forename: D
authors.initials: D
authors.lastname: Adcock
authors.affiliation: Baylor College of Medicine, Houston, TX, USA.|Texas Children's Hospital, Houston, TX, USA.
authors.forename: J
authors.initials: J
authors.lastname: Teruya
mesh_terms: D015415:Biomarkers / Q000097:blood*; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D006801:Humans; D007231:Infant, Newborn; D019934:International Normalized Ratio / Q000379:methods*; D009752:Nutritional Status; D011237:Predictive Value of Tests; D011247:Pregnancy; D039401:Prenatal Nutritional Physiological Phenomena; D011486:Protein C / Q000032:analysis; D011498:Protein Precursors / Q000097:blood*; D017293:Protein S / Q000032:analysis; D011516:Prothrombin; D011517:Prothrombin Time / Q000379:methods; D014812:Vitamin K / Q000008:administration & dosage / Q000097:blood*; D014813:Vitamin K Deficiency / Q000097:blood*
chemical_list: D015415:Biomarkers; D011486:Protein C; D011498:Protein Precursors; D017293:Protein S; D014812:Vitamin K; C008208:acarboxyprothrombin; D011516:Prothrombin
keywords: INR; PIVKA-II; newborns; protein C; protein S; vitamin K deficiency