Is the additive used in the purple cap tube potassium EDTA?

 

When taking blood from a hospital, it is easy to find caps with different colors on the tubes, but the most common one is a purple cap tube. Basically, 70% - 80% of people who go to the hospital for treatment will encounter this tube when drawing blood. So what does this tube contain? Or would a more professional person ask if the additive in the tube is potassium EDTA?

 

First, the purple cap tube contains an anticoagulant, an additive that prevents blood from clotting. However, this additive belongs to EDTA salt or ethylenediamine tetraacetate salt. Therefore, from this perspective, the statement that the additive used in the purple cap tube is potassium EDTA is correct. However, EDTA salts are generally divided into potassium or sodium salts, specifically including potassium EDTA, potassium EDTA, and disodium EDTA. The purple cap tube additive can be any of them. Therefore, the above statement would be too narrow in this perspective, correct but not comprehensive.

 

Overall, EDTA salts can fully protect blood cells, do not affect the count and size of white blood cells, have minimal impact on the morphology of red blood cells, and have an inhibitory effect on platelet aggregation. Therefore, EDTA tubes or purple cap tubes are mostly used for blood routine testing, but it should be noted that this tube cannot be used for blood coagulation or platelet function testing. Generally, it is necessary to reverse 5-8 steps as soon as possible after blood collection to achieve sufficient anticoagulant effect. In addition, if you want to obtain more accurate test results for EDTA anticoagulant tubes, you should complete the test within 24 hours of blood collection.

 

EDTA salts have similarities and differences. Among EDTA salts, potassium EDTA is more widely used. The solubility of disodium EDTA is higher than that of disodium EDTA, with complete dissolution, fast anticoagulation speed, and good effect; The solubility of potassium II is not as good as that of potassium III, but potassium III is mostly used as a liquid additive in glass tubes, which can lead to dilution of the sample, which can affect the detection effect. In addition, when the concentration of red blood cells is 7.5 mg/ml, EDTA tripotassium is more likely to cause red blood cell shrinkage.

 

For EDTA salts, it is difficult to define which anticoagulant is better, each has its own merits, and it is difficult to distinguish between them. Products are right and wrong, and everything comes into being according to the needs of customers. As an old brand in the blood collection additive industry, Desheng can provide you with each of the above EDTA salts, and we also have everything else. If you need anything, we are always waiting for your visit.