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A pseudothrombocytopenia false-positive result may occur when automated platelet counting devices are used. As a means of double checking the results, the patient's blood sample is often examined under a microscope. If the clumping is visible and the number of platelets appears normal, pseudothrombocytopenia may be concluded.
Giant platelet disorder; Two giant platelets (stained purple) are visible in this image from a light microscope (40×) from a peripheral blood smear surrounded by red blood cells. One normal platelet can be seen in the upper left side of the image (purple) and is significantly smaller in size than the red blood cells (stained pink). Specialty ...
Rouleaux formation on wet smear. Rouleaux (singular is rouleau) are stacks or aggregations of red blood cells (RBCs) that form because of the unique discoid shape of the cells in vertebrates. The flat surface of the discoid RBCs gives them a large surface area to make contact with and stick to each other; thus forming a rouleau.
Platelet clumps in a blood smear. Platelet aggregation begins minutes after activation, and occurs as a result of turning on the GPIIb/IIIa receptor, allowing these receptors to bind with vWF or fibrinogen. [5] Each platelet has around 60,000 of these receptors. [31]
One common definition of thrombocytopenia requiring emergency treatment is a platelet count below 50,000/μL. [5] Thrombocytopenia can be contrasted with the conditions associated with an abnormally high level of platelets in the blood – thrombocythemia (when the cause is unknown), and thrombocytosis (when the cause is known). [6] [7]
High platelet counts can occur in patients with polycythemia vera (high red blood cell counts), and is an additional risk factor for complications. [ citation needed ] A very small number of people report symptoms of erythromelalgia , a burning sensation and redness of the extremities that resolves with cooling, or aspirin or both.
Platelets which have been bound by antibodies are taken up by macrophages in the spleen (which have Fc receptors), and so removal of the spleen reduces platelet destruction. The procedure is potentially risky in ITP cases due to the increased possibility of significant bleeding during surgery.
This results in platelet activation and the formation of platelet microparticles, which initiate the formation of blood clots; the platelet count falls as a result, leading to thrombocytopenia. [1] [7] In addition, the reticuloendothelial system (mostly the spleen) removes the antibody-coated platelets, further contributing to the thrombocytopenia.