Baylor College of Medicine, Houston, TX, USA
Texas Children’s Hospital, Houston, TX, USA
| [c] Esoterix Coagulation, Laboratory Corporation of America Holdings, Englewood, CO, USA
Address for correspondence: Jun Teruya, MD, DSc, Professor of Pathology & Immunology, Pediatrics, and Medicine, Baylor College of Medicine, Chief, Division of Transfusion Medicine & Coagulation, Texas Children’s Hospital, 6621 Fannin St, Suite WB1100 Houston, TX 77030, USA. Tel.: +1 832 824 1879; Fax: +1 832 825 5858; E-mail: firstname.lastname@example.org.
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). CONCLUSION: 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.
Keywords: PIVKA-II, vitamin K deficiency, newborns, INR, protein C, protein S