Vitamin K Deficiency and Prothrombin Levels. Effect of Vitamin K Administration. ∗

Abstract

Summary

A detailed study was made concerning the rate at which the plasma prothrombin level falls when newly hatched chicks are placed on a vitamin K-deficient diet. The whole blood clotting time becomes prolonged when the prothrombin level falls to about 30% of the normal level for chicks of the same age. Hemorrhages make their appearance when the prothrombin is approximately 10% of normal.

It was also shown that large doses of vitamin K correct the plasma prothrombin deficit almost completely within 6 hours. Somewhat smaller doses effect partial recovery in 6 hours, and almost complete recovery in 18 hours.

Questions of assay technic and of therapeutic needs are discussed.