[Antithrombin III determination in horses. Reference values and acquired antithrombin III deficiency].

The study focuses on the measurement of Antithrombin III (AT III) in both healthy and sick horses, determining reference values for the substance, observing how these change after surgical procedures, and examining the links between reduced AT III levels and various health conditions.

Methodology & Reference Values

• The researchers used a test known as the chromogenic substrate Chromozym TH to measure the levels of AT III, a protein that helps control blood coagulation, in horses.
• They established reference values for adult horses, finding average AT III values of 18-25 IU per ml of plasma, with the average horse’s plasma showing 84-118% AT III activity.
• The precision and accuracy of these tests were found to be high, with an intra assay coefficient of variation of less than 2%, and an accuracy of 10%, indicating reliability in their results.

Changes in AT III Activity After Surgery

• The researchers found that levels of AT III in horses decreased in a biphasic pattern following surgical procedures, reaching the lower end of the reference values by the second postoperative day.

AT III Deficiencies and Link to Disorders

• AT III deficiencies were also found in horses suffering from a range of health conditions, including liver disease, disseminated intravascular coagulation (DIC), and glomerulonephritis.
• Through following the health progression of these horses, the team was able to identify differences in the dynamics of acquired AT III deficiencies and factors promoting coagulation.
• Of the 35 horses with decreased AT III levels, 12 suffered from phlebothrombosis, blockage of a vein due to a blood clot, in the jugular veins.
• The researchers suggested that acquired AT III deficiencies may promote the development and progression of phlebothrombosis or thrombophlebitis in horses.