Confirmation, or investigation of minor deficiency, can be performed by testing proteins produced in the absence of vitamin K, the most established assay being for PIVKA-II.

[2] Controversy arose in the early 1990s regarding routine supplementation, when two studies suggested a relationship between parenteral administration of vitamin K and childhood cancer.

[7] However, both studies have been discredited on the basis of poor methodology and small sample sizes, and a review of the evidence published in 2000 by Ross and Davies found no link between the two.

[8] Treatment of established bleeding depends on the location but includes vitamin K1 (phylloquinone; phytomenadione; phytonadione) administration which restores the prothrombin time rapidly.

Severe bleeding may require blood products such as fresh frozen plasma (FFP), a prothrombin complex concentrate (PCC).