✅ Antithrombin - excess or deficiency

Antithrombin is an important protein involved in the blood clotting process. By inhibiting the activity of blood clotting factors, it delays blood clotting. What are the he alth effects of deficiency and excess of antithrombin? Who should perform the test?

Antithrombin , abbreviatedATis a protein belonging to the group of serine protease inhibitors. Its function is to inhibit blood coagulation factors such as thrombin, coagulation factor IXa, XIa, XIIa, and Kalkrein. Antithrombin is produced in the liver, endothelial cells of blood vessels and platelets. Formerly, antithrombin was called antithrombin III. The function of antithrombin is to delay blood clotting by forming a complex with thrombin which is then eliminated by the cells of the immune system. Heparin is a factor accelerating the rate of binding of antithrombin to thrombin and coagulation factors.

Antithrombin - congenital deficiency

Congenital antithrombin deficiency is genetically determined and occurs in 1: 5,000 people. Symptoms of the disease in the form of recurrent venous thrombosis appear before the age of 40. Heparin treatment is ineffective in people with congenital antithrombin deficiency.

Congenital antithrombin deficiency comes in two forms:

quantitative deficiency (type I) , which occurs most often and is associated with a decreased concentration of antithrombin by more than 50%
qualitative deficiency (type II) , which results from the loss of function by antithrombin as a result of a point mutation. In the results of the research, this type of deficiency is manifested by the correct concentration of antithrombin, but with its reduced activity

Antithrombin - what is the test and how much does it cost?

Antithrombin activity and concentration are measured in venous blood taken from the elbow bend into sodium citrate. Then, in the laboratory, the so-called platelet poor plasma. Antithrombin testing should be performed on an empty stomach, preferably between 6:30 a.m. and 9:00 a.m. and before starting or 10 days after completing heparin therapy.

In the laboratory, two methods are used to determine antithrombin activity:

amidolytic- consisting in measuring the rate of splitting of a substrate in a chemical reaction to a colored one using a spectrophotometerproduct
coagulometric- measuring the rate of clot formation after adding fibrinogen

Immunochemistry is used to determine the concentration of antithrombin. The price of an antithrombin activity test in a commercial laboratory costs PLN 30-80.

Antithrombin deficiency

Normal values for antithrombin concentration are 0.19-0.31 g / l, while its activity should be in the range of 80-120%. In newborns, antithrombin levels are approximately 50% lower than in adults and reach normal levels at 6 months of age.

Decreased activity or low concentration of antithrombin is observed in:

severe liver damage
loss of proteins, e.g. nephrotic syndrome, burns
disseminated intravascular coagulation (DIC) syndrome
sepsis
extensive surgical procedures
multi-organ injuries
unfractionated heparin treatment
taking estrogen
pregnancy
cancer
heavy blood loss
kidney failure
pulmonary embolism
in congenital antithrombin deficiency

It is worth noting that congenital or acquired antithrombin deficiency causes thrombosis and / or heparin ineffectiveness. Hence, antithrombin testing is also ordered in people with resistance to heparin treatment.