What Is EDTA Tube And How To Use It In Specimen Process?

Ethylenediaminetetraacetic acid, or EDTA, is a commonly used component of blood collection. EDTA mainly uses purple top(lavender top). EDTA is mostly used to remove metal ions from solutions and alter the characteristics of ions because of its strong capacity to interact with metal ions. It is an effective chelating agent as a result. Chelating is the process of combining metal ions with a chelating agent.

How To Use It In Specimen Process (Lavender top or Purple top)?

Blood analysis usually makes use of EDTA. For CBC/FBC blood samples, it acts as an anticoagulant by chelating the calcium present and stopping the coagulation process while preserving the form of the blood cells. This makes it possible to perform complete blood counts (CBCs) on whole blood without altering the outcomes.

What is the difference between K₂ EDTA and K₃ EDTA(Both use Lavendor top or Purple top)?

The fundamental distinction between K₂ EDTA and K₃ EDTA is the presence of two chelated potassium ions in K₂ EDTA as opposed to three in K₃ EDTA. Furthermore, K₃ EDTA has no effect on the MCV of red blood cells at greater concentrations, whereas K₂ EDTA marginally increases the MCV (mean corpuscular volume) of red blood cells at higher concentrations.

K₂ EDTA (dipotassium ethylenediaminetetraacetic acid) is a potent anticoagulant used to keep blood in lanvender top or purple top blood collection tubes for complete blood counts (CBC). In most cases, whole blood is kept in these tubes. But K₂ EDTA has two potassium ions bonded to the molecule of EDTA.

Additionally, EDTA is a chelating agent that can sequester metal ions in a mixture, such as calcium ions and ferric ions, reducing their reactivity. K₂ EDTA's primary role in the blood sample is therefore to chelate calcium ions from the combination. Furthermore, calcium ions are needed for the process of blood coagulation. However, the presence of EDTA in the material prevents the calcium ions from being used in this process, preventing coagulation.

K₃ ETDA is an alternate type of K₂ EDTA used during blood collection for standard hematological assays. K₃ EDTA, as opposed to K₂ EDTA, has three potassium ions bonded to EDTA. However, for two reasons, the International Council for Standardization in Haematology advises using K₂ EDTA as the anticoagulant:

• The shrinkage of red blood cells rises with increasing EDTA concentration in K₃ EDTA (11% shrinkage with 7.5 mg/ml blood).

• K₃ EDTA significantly increases cell volume upon standing.

How long does blood last in lavender top (purple top) tube?

Blood can be kept in lavender top tube at 4°C for 12, 24 or 36 hours before to processing, or it can be frozen at -80°C in lavender top tube for 20 days before being thawed under carefully monitored circumstances. Stability of the samples can different based on variety of assays used.

Reference:

[1]https://www.skgmed.com/What-is-the-Difference-Between-K2-EDTA-and-K3-EDTA-id47713377.html

[2]https://short-facts.com/what-does-edta-mean-in-a-blood-test/

[3] https://www.thehealthboard.com/what-is-an-edta-anticoagulant.htm