The measurement of antithrombin III concentration (antigen concentration) is used to evaluate the pathological results of the antithrombin III activity test which is recommended as the first-line test for antithrombin III evaluation. The measurement of antithrombin III concentration is also used in the diagnosis of antithrombin deficiency of acquired or congenital etiology, in combination with the measurement of antithrombin activity as well as as a complementary test to the diagnosis and management of certain carbohydrate-deficient glycoprotein syndromes.
During hemostasis, a substance called thrombin stimulates fibrin formation by fibrinogen. This fibrin then forms a fixed clot at the point of injury. The excess of the coagulation factors remaining after hemostasis are inactivated by fibrin inhibitors that prevent coagulation when not needed. One such substance is antithrombin III (AT-III), a protein synthesized by the liver. The action of antithrombin III is catalyzed by heparin. Its role is to inactivate thrombin and other coagulation factors, thereby inhibiting the coagulation process. The appropriate balance between thrombin and antithrombin III makes hemostasis possible. However, if this balance is disturbed, problems may arise. For example, if there is a congenital deficiency of antithrombin III, coagulation will not be sufficiently inhibited, resulting in a state of hypercoagulability which poses a risk of thrombosis.
What Do Pathological Values Mean?
- Increase: Vitamin K deficiency. Medications: anabolic steroids, androgens, oral contraceptives containing progesterone, warfarin.
- Decrease: Cirrhosis, congenital antithrombin III deficiency, deep vein thrombosis, disseminated intravascular coagulation, hypercoagulability condition, advanced pregnancy / early postpartum, liver transplantation, malnutrition, nephrotic syndrome, postoperative period, pulmonary embolism, sepsis. Medications: oral contraceptives containing estrogen, fibrinolytics, heparin, L-asparaginase.
Important Note
Laboratory test results are the most important parameter for the diagnosis and monitoring of all pathological conditions. 70%-80% of diagnostic decisions are based on laboratory tests. The correct interpretation of laboratory results allows a doctor to distinguish "healthy" from "diseased".
Laboratory test results should not be interpreted from the numerical result of a single analysis. Test results should be interpreted in relation to each individual case and family history, clinical findings, and the results of other laboratory tests and information. Your personal physician should explain the importance of your test results.
At Diagnostiki Athinon we answer any questions you may have about the test you perform in our laboratory and we contact your doctor to get the best possible medical care.
