What is the anticoagulation principle of different blood anticoagulants

There are many kinds of anticoagulants. Although they are all for anticoagulation, the anticoagulants to be selected in different tests are also different. How to choose the right anticoagulant in the process of use is very important. Otherwise, the wrong choice may lead to the deviation of test results, which may be very different for patients. Now Desheng takes you to understand the anticoagulant mechanism of different anticoagulants.

Heparin is widely distributed in almost all tissues such as lung, liver, spleen and the granules of mast cells and basophils around blood vessels. It is a mucopolysaccharide with sulphuric acid group, with an average molecular weight of 15000 (2000-40000).

Heparin is the best anticoagulant in the determination of blood chemical composition. Its anticoagulant mechanism is to inhibit the interaction between factor IX a, VIII and PF3 at low concentration together with anticoagulant II, and to enhance the inactivation of serine protease by antithrombin III, so as to prevent the formation of thrombin; it also inhibits the self catalysis of thrombin and the inhibition of factor X. Heparin anticoagulant should be used in a short period of time, otherwise the blood can coagulate if it is placed too long.

Ethylenediaminetetraacetic acid (EDTA) has disodium, dipotassium and Tripotassium salts. EDTA salt had little effect on the morphology of red blood cells and white blood cells.

EDTA is one of the most common and important anticoagulants and reagents in clinical work. Its mechanism is to prevent blood coagulation by forming a stable chelate with calcium ion in water phase. EDTA can also affect platelet aggregation and leukocyte phagocytosis, and is not suitable for hemostatic test and platelet function test. The salts of EDTA include potassium, sodium and lithium, which are soluble in water. The solubility of potassium is higher than that of sodium. The potassium salt of EDTA is the best for whole blood cell count.

Citrate can form a soluble chelate with calcium ions in blood, thus preventing blood coagulation. It was used with blood in the ratio of 1:9 or 1:4.

Citrate is mainly sodium citrate. Its anticoagulant principle is that it can combine with Ca2 + in blood to form chelate, which makes Ca2 + lose coagulation function, and the coagulation process is blocked, so as to prevent blood coagulation. Sodium citrate 6mg can anticoagulate 1ml blood, strong alkaline, not suitable for blood test and biochemical test.

Oxalate is also a common anticoagulant with the advantage of high solubility. The commonly used oxalate anticoagulants are sodium oxalate, potassium oxalate and ammonium oxalate. The concentration of sodium oxalate is 0.1 mol / L, and the ratio of sodium oxalate to blood is 1:9.

After oxalate dissolves, the dissociated oxalate and Ca2 + in the sample form calcium oxalate precipitation, which makes Ca2 + lose the coagulation function and block the coagulation process. Oxalate can cause platelet aggregation and affect the morphology of leukocytes, so it can not be used for the differential count of leukocytes and platelets.