laboratory findings
Last reviewed 01/2018
- prolonged prothrombin time
- prolonged partial thromboplastin time - but less so than for PT
- fibrinogen level, thrombin time and platelet count are unaffected
If the prothrombin time is prolonged, there are two alternatives for determining if vitamin K deficiency is the cause:
- positive response to therapeutic trial of vitamin K supplements
- plasma radioimmunoassay of the non-carboxylated precursor of prothrombin; shown to be at increased concentration