31/05/2024
Medicine residents!!!! Patient came with platelet counts of 30,000, with no history of bleed. You ordered a peripheral film morphology review? Here what you see. What is this?
Image: The blood project
Basically a lot of times due to the EDTA anticoagulant in the blood tube, phenomenon of platelet clumping is seen. This happens due to naturally occurring autoantibody against an epitope on GPIIbIIIa thats exposed by the EDTA. This causes, in vitro ( only in the tube and not in your body) clumping of platelets.
The counting machine has a specific size to measure a platelet as a platelet and so these clumps are missed and a falsely low count is reported by the automated analyzer. Which in actual is normal or atleast far higher than what reported.