Vitamin K in the cat with liver disease before biopsy
10-year-old cat, anorexic for 2 weeks, jaundiced, with suspected cholangitis or hepatic lipidosis. You plan to place an oesophagostomy tube and take liver samples, but the prothrombin time is prolonged and there is no active bleeding.
What is most appropriate before the procedures?
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A. Subcutaneous vitamin K1 12–24 hours before and reassess coagulation
Correct. Cholestasis, anorexia and intestinal disease reduce vitamin K absorption, and many cats with liver disease are deficient. The parenteral route avoids the absorption problem; the intravenous route is avoided because of the risk of anaphylactoid reactions.
B. Fresh frozen plasma for every jaundiced cat, without vitamin K
Plasma is reserved for active bleeding or when there is no time to wait. If the cause is vitamin K deficiency, vitamin K1 corrects it more simply and durably.
C. Oral vitamin K1 on the day of the procedure
Vitamin K is fat-soluble and needs bile salts to be absorbed: in cholestasis the oral route is unreliable, and there is not enough time for factors to be synthesised.
D. Not needed: if platelets are normal, the cat will not bleed
Factors II, VII, IX and X depend on vitamin K; a normal platelet count does not compensate for their deficiency and the risk of bleeding after biopsy is real.
lightbulb Key takeaway
Consider parenteral vitamin K1 in every cat with cholestasis, lipidosis or severe enteropathy before a feeding tube, a biopsy or a cystocentesis. Normal coagulation tests do not completely exclude bleeding: monitor the cat after the procedure.
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Updated: October 31, 2026 · Educational content for veterinary professionals. It does not replace current clinical guidelines or the judgement of the attending veterinarian.