I am currently doing an experiment which involves changing the techniques in staining of blood smear. I use expired EDTA tubes to store the blood collected, does the expired tube will affect the morphology of blood in any way when I view it under the light microscope?
EDTA (ethylenediaminetetraacetic acid) is the most commonly used anticoagulant in evacuated tubes. It inhibits the clotting process by removing calcium from the blood. So EDTA acts as chelating agent. This chemical does not distort blood cells, making it ideal for hematology use. If EDTA is expired then Calcium will not chelate & cell morphology will not be preserved.
Ref: Gordan HG, Larson NL. Use of sequestrene as an anticoagulant. Am J Clin Pathol. 1955;23:613-18.
Hi Afrina
A few questions about your expired EDTA tubes:
1. Are the tubes clinical grade, sterile plastic tubes and the seal / lid intact?
2. If yes, are they vacutainer-type tubes and still evacuated of air? Is the EDTA still dry?
3. If clinical grade tubes, did you collect the specified volume of blood in order to ensure the correct EDTA:blood ratio?
4. Have the tubes been stored correctly for the entire time before you used them for your blood samples?
5. Where the EDTA tubes effective to fully anti-coagulate your blood samples?
6. How long have the tubes been expired when you used them?
If your answer is "yes" to Q1-5, then chances are that it should be OK. EDTA is very stable.
Regards, Rosemary
Agreed, EDTA is very stable. The expiration date is more relevant for the loss of vacuum in the tube so that the correct amount of blood is not drawn in during the blood draw.
I would be concern about the actual loss of dead cells and development of vacuoles and formation of precipitates in the cells. And the underlying clinical condition could also contribute to change such as an elevated blood glucose and renal failure.
I completely agree with Rosemary and Diane. If the amount of blood is equal to that of not expired tubes and if the blood does not clot there is not reason to think about morphological changes of leukocytes as well as of RBC and PLT.
If a blood collection tube is used past its expiration date, the vacuum may not draw the amount of blood needed to fill the tube completely. ... If the tube contains an anticoagulant, it may not work effectively (may not prevent the blood from clotting)
- Badges
- Science topic
- Similar topics
- Biological Science
- Microbiology
- Virology
- Virus