The main points of using EDTA-K2 as anticoagulant for blood collection tube
EDTA-K2 refers to dipotassium ethylenediaminetetraacetic acid. It is an EDTA salt. It is commonly used as an anticoagulant in vacuum blood collection tubes. Due to its wide range of applications, the method of use in non-application is also different. Here Explain the main points of its use as an anticoagulant.
EDTA-K2 blood anticoagulation principle:
EDTA-dipotassium has a molecular weight of 404.6 and a pH of 3.8-5.8. It is usually prepared by the reaction of EDTA and potassium hydroxide, and then the crystal is dehydrated and dried by controlling the pH to obtain the finished powder. When it is formulated into a solution, it will dissociate EDTA anions and EDTA acid, which can quickly complex calcium ions in the blood, thereby preventing blood coagulation, and can inhibit platelet aggregation.
The difference between EDTA-K2 and other anticoagulants:
Dipotassium EDTA is usually used as a blood collection tube anticoagulant for blood cell counting. Its melting point is lower than that of tripotassium EDTA, and its anticoagulation rate is slower; but its solubility is higher than that of disodium EDTA, so disodium EDTA is used less; lemon Sodium as an anticoagulant is generally used for coagulation tests (3.2%, 1:9) and erythrocytes (3.8%, 1:4).
Key points for preparation of EDTA-K2 anticoagulant solution:
According to the requirements of Appendix YY of the YY0314-2007 standard, the content of EDTA-K2 and EDTA-K3 in each mL of blood is 1.5-2.2mg, and we take the intermediate value of 1.8mg/mL when formulating the reagent. Follow the steps below during configuration:
1. First determine the amount of blood collected in the blood collection tube and the amount of anticoagulant added, usually the amount of blood collected is 2mL, the amount of anticoagulant added is 20uL, then the concentration of dipotassium in EDTA is 1.8*2/0.02=180mg/mL, ie 180g/ L.
2. Weigh the amount of dipotassium EDTA according to the volume of the configuration solution. If 500mL is configured, 90g is weighed, and if 2L is configured, 360g is weighed. Based on the amount of 20uL added to each tube, 2L dipotassium solution can be applied to 100,000 anticoagulation tubes.
3. The prepared solution should be stored at a low temperature of 0-4℃, and the storage time should not exceed 7 days, so it is best to use it now. It should be noted that if the blood collection volume in the anticoagulation tube is 3mL or 5mL, the concentration of dipotassium EDTA solution we can configure is 180g/L without increasing its concentration, and limited consideration is given to increasing the amount of addition in each tube to 30uL or 50uL, Because the solubility of EDTA-K2 is limited, and too high a concentration may cause local osmotic pressure to increase and cause local blood cells to rupture to produce hemolysis.
When using EDTA dipotassium anticoagulation tube for blood collection, there is another point to note. The anticoagulation of EDTA salt is not irreversible anticoagulation. The test should be completed within 24 hours after blood collection. The storage time of EDTA salt anticoagulant specimens is: white blood cell count can be stored for 48 hours at 4 ℃, and not more than 24 hours at 23 ℃. Platelet count can be stored for 24 hours at 4℃. EDTA salt can inhibit platelet aggregation, but it cannot completely prevent platelet aggregation. Sodium citrate anticoagulant can be used for platelet detection and verification.
Each kilogram of EDTA-K2 can meet the use of nearly 300,000 anticoagulation tubes, the cost is only a few hundred yuan, but it can affect the testing of hundreds of thousands of samples, so it is recommended to choose an old brand blood collection reagent manufacturer like Desheng And, together with its separation gel, it can guarantee high-quality blood collection tubes and high-quality blood samples.
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