Protein C
Manifestation of purpura fulminans as it is usually associated with reduced protein C plasma concentrations of &lt;5 mg IU/dL. The normal concentration of plasma protein C is 70 nM (4 µg/mL) with a half live of approximately 8 hours. Healthy term neonates, however, have lower (and more variable) physiological levels of protein C (ranging between 15-55 IU/dL) than older children or adults, and these concentrations progressively increase throughout the first 6 months of life. Protein C levels may be &lt;10 IU/dL in preterm or twin neonates or those with respiratory distress without manifesting either purpura fulminans or disseminated intravascular coagulation.