Pivka

PIVKA stands for protein induced by vitamin K absence or antagonist. It refers to undercarboxylated forms of vitamin K–dependent clotting factors, most notably prothrombin (factor II). Under normal gamma-carboxylation in the liver, these factors gain a gamma-carboxylglutamic acid domain essential for calcium binding. When vitamin K is deficient or inhibited by antagonists such as warfarin, the gamma-carboxylation process is incomplete, yielding PIVKA molecules that lack functional gamma-carboxyl groups.

The best characterized PIVKA form in clinical practice is PIVKA-II, known as des-gamma-carboxy prothrombin (DCP). It is detectable in serum and is elevated in several conditions, particularly hepatocellular carcinoma (HCC). PIVKA-II is distinct from, but often measured alongside, conventional coagulation tests and other tumor markers.

Clinically, PIVKA-II is used as a biomarker to aid in the diagnosis and surveillance of HCC, frequently in combination with alpha-fetoprotein (AFP) and imaging studies. It may be more sensitive than AFP in some cohorts and can correlate with tumor burden and vascular invasion, but it is not specific to HCC and can rise with vitamin K deficiency, cirrhosis, hepatitis, or recent anticoagulant therapy.

Assays rely on immunoassays to quantify PIVKA-II; results are influenced by vitamin K status and recent anticoagulant use. Because of limited specificity, PIVKA-II is best interpreted as part of a multi-marker approach rather than a stand-alone diagnostic test.