What does platelet clumping indicate?
Platelet clumping occurs when the blood platelets responsible for coagulation stick to one another to form clusters. The presence of platelet clumping has no clinical consequences other than preventing instruments from properly counting blood platelets.
What is the most common reason for platelet clumping in a sample?
Platelet clumping is most commonly caused by pre-analytic errors such as improper or delayed sample mixing, clotted sample, over-filled or underfilled tubes, and time delay between sample collection and testing. It can also be an ex vivo phenomenon due to EDTA-dependent antibodies.
What is platelet clumping in EDTA?
Platelet clumping is a common laboratory phenomenon that complicates or precludes reporting of platelet count. It is often, but not always, a phenomenon commonly caused by the anticoagulant EDTA.
Why is EDTA preferred as anticoagulant in platelets?
EDTA has been recommended as the anticoagulant of choice for hematological testing because it allows the best preservation of cellular components and morphology of blood cells. One rare drawback of EDTA as anticoagulant is spuriously low platelet count or pseudothrombocytopenia.
How do you prevent platelets from clumping?
Eighty milligrams of aspirin was given prophylactically to mitigate platelet clumping if the platelet count was ≥80,000/μL.
Are platelets supposed to clump?
A normal platelet count, even with clumping seen on a smear, is still usually estimated to be normal (or may occasionally be increased.) Thrombocytopenia, on the other hand, can be a challenge in the hematology laboratory.
How do you fix platelet clumping?
Many labs will have an alternate tube drawn or use another method to help resolve the clumping. Less commonly used tubes are CTAD (trisodium citrate, theophylline, adenosine, dipyridamole) and heparin. CTAD acts directly on platelets and inhibits platelet factor 4 thus minimizing platelet activation.
How do you stop platelets from clumping?
What can cause clots in EDTA specimens?
A common cause of clotted EDTA samples is improper mixing of sample tubes after collection. This is often an avoidable event, overcome by inverting the tube 8-10 times immediately after collection to mix the blood thoroughly with the EDTA. These should be gentle inversions, avoiding rigorous shaking.
What causes EDTA induced pseudothrombocytopenia?
EDTA-induced pseudothrombocytopenia, the most frequently seen form in clinical practice, occurs mainly due to reaction of antiplatelet antibodies including cold agglutinin type of IgG, IgM and IgA with platelet surface antigens.
What causes blood to clump?
They form in your bone marrow, a sponge-like tissue in your bones. Platelets play a major role in blood clotting. Normally, when one of your blood vessels is injured, you start to bleed. Your platelets will clot (clump together) to plug the hole in the blood vessel and stop the bleeding.
What causes clumping to occur?
Clumping is most often due to the anticoagulant ethylenediaminetetraacetic acid (EDTA) but may also result from autoantibodies, such as cold agglutinins. The presence of giant platelets and platelet satellitism may also yield falsely low automated platelet counts.
What is the best way to resolve platelet clumping in sample subjected to automated hematological?
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- The first step to resolve platelet clumping is to vortex the specimen for one to two minutes at or near the highest setting, which will be successful in approximately 50 percent of cases.
Does EDTA affect platelet count?
It inhibits clotting by removing or chelating calcium from the blood. EDTA most important advantage is that it does not distort blood cells, making it ideal for the most hematological tests. It is known to cause erroneous results of platelet counts by automated hematological analysers yielding low platelets counts.
How do you remove clots from EDTA tubes?
It is never appropriate to physically remove the clots from a tube of blood. The tube must be discarded, and the specimen must be recollected. The person collecting the blood whether a phlebotomist, tech, or nurse is responsible for ensuring the quality of each specimen collected.
What is the normal platelet count with EDTA in a smear?
EDTA whole blood smear had many platelet clumps noted (EDTA induced thrombocytopenia). Conclusion: Platelets are adequate and estimated to be about 200,000/μL. Figure 1. Results from warmed EDTA tube (left) and Na Citrate tube (right). Image 1. Clumped platelets seen with EDTA. Image 2. Normal platelet count with no clumping seen with Na Citrate.
What is the platelet clumping protocol?
The Platelet Clumping Protocol is used to resolve falsely decreased platelet counts (pseudothrombocytopenia) in patients whose platelets clump in the presence of EDTA. The lab will test the citrate tube and the EDTA tube submitted for the CBC or platelet count ordered concurrently.
What causes platelets to clump in a sodium citrate tube?
These antibodies are EDTA-dependent, though they sometimes cause clumping in 3.2% sodium citrate tubes, and they are not temperature-dependent. In this case, the antibody causes in vitro platelet clumping instead of satelliting.
Should the tube be full for platelet clumping?
Tube must be full. The Platelet Clumping Protocol is used to resolve falsely decreased platelet counts (pseudothrombocytopenia) in patients whose platelets clump in the presence of EDTA. The lab will test the citrate tube and the EDTA tube submitted for the CBC or platelet count ordered concurrently.