Anticoagulants are substances that prevent blood from clotting. An ethylenediamine tetraacetic acid (EDTA)anticoagulant, therefore, uses this type of acid to stop the clotting process. The EDTA anticoagulant is often used in laboratory diagnostic tests, such as the complete blood count (CBC), because it retains the original shape and size of the cells. This is because the EDTA anticoagulant can bind with the calcium present in blood, thus preventing the start of the coagulation cascade, which is the process by which blood clot formation occurs.
Depending on the type of test to be done, the tube of blood collected for a test, may come with an anticoagulant inside. The tube that comes with an EDTA anticoagulant is commonly seen having a lavender cover or cap. EDTA often is used in the CBC tests for hemoglobin, hematocrit, red blood cell (RBC) count, white blood cell (WBC) count, platelet count, and lymphocyte differential count.
The hematocrit often measures the percentage of RBC present in the blood. Hemoglobin is a protein inside the RBC that is capable of carrying and delivering oxygen to different parts of the body. A decreased hematocrit can indicate anemia and dehydration. Hemoglobin is frequently decreased in conditions such as deficiency in iron and Vitamin B 12, bleeding problems, and bone marrow disorders.
RBC and WBC counts can also help diagnose a variety of health conditions. The platelet count measures the number of platelets, the blood components that can also prevent blood clots from forming. Patients with very low counts may suffer from bleeding tendencies. The lymphocyte differential count usually identify and record the number of types of WBCs present in the blood sample, thus cells should retain their original shapes and structures for an accurate result.
There is often a standard amount of EDTA anticoagulant incorporated inside tubes of blood meant for testing. The phlebotomist, a trained person who collects blood from the arm, often knows the required amount of blood to be placed inside the tube. If insufficient blood is collected, cells may shrink and undergo some changes, thus making the laboratory test result abnormal and not reliable. Putting more blood than required may also make the results less reliable.