Changes

The PIVKA test is modified version of PT that is designed to be more sensitive than PT for abnormalities in the vitamin-K dependent clotting factors. Diluted plasma is used to give longer clotting times, and a test-specific reagent is added. The PIVKA test is reported to be sensitive to both increases in PIVKAs and decreases in the functional coagulation factors II, VII, IX and X, although there is some debate as to whether PIVKAs actually inhibit the reaction. Although intended to be more sensitive than the PT for factors of interest, studies in dogs have shown that a PIVKA test offers little diagnosic advantage⁴. Additionally, only certain laboratories offer the test and the turnaround time is longer than PT.  

The PIVKA test is modified version of PT that is designed to be more sensitive than PT for abnormalities in the vitamin-K dependent clotting factors. Diluted plasma is used to give longer clotting times, and a test-specific reagent is added. The PIVKA test is reported to be sensitive to both increases in PIVKAs and decreases in the functional coagulation factors II, VII, IX and X, although there is some debate as to whether PIVKAs actually inhibit the reaction. Although intended to be more sensitive than the PT for factors of interest, studies in dogs have shown that a PIVKA test offers little diagnosic advantage⁴. Additionally, only certain laboratories offer the test and the turnaround time is longer than PT.  

The PIVKA test is prolonged in vitamin K deficiency due to low vitamin K-dependent factor concentrations. This is usually due to vitamin K antagonism by anticoagulant rodenticides but can also be seen in cholestatic liver disorders, e.g. hepatic lipidosis in cats. Early studies suggested that the PIVKA test may be the first coagulation test to be prolonged after experimental administration of anticoagulant rodenticides to dogs, however no further studies have been done to support this claim. The PIVKA test, like the PT, is prolonged in some dogs with DIC and dogs with factor VII deficiency, indicating that it is not specific for vitamin K deficiency. Some authors believe that the PIVKA test is a useful guide as to which patients with liver disease and abnormal coagulation results will respond to vitamin K therapy (by normalization of the coagulation times). The PIVKA test is normal in dogs with inherited deficiencies of factors VIII, IX, and XI, and prekallikrein.

The PIVKA test is prolonged in vitamin K deficiency. This can result from anticoagulant rodenticide toxicity or cholestatis. Some animals in disseminated intravascular coagulation also show a prolonged PIVKA test.

==Tests Evaluating Fibrinolysis==

==Tests Evaluating Fibrinolysis==