THROMBOCYTES / PLATELETS
Platelets, also called thrombocytes are a component of blood whose function (along with the coagulation factors) is to react to bleeding from blood vessel injury by clumping, thereby initiating a blood clot. Circulating inactivated thrombocytes / platelets are lens-shaped structures 2–3 µm in greatest diameter.
Normal platelet concentrations
Normal thrombocytes / platelets concentrations in whole blood range from 150-400 plt/nl. The number of platelets varies across individuals.
On a stained blood smear (as shown on the image), thrombocytes / platelets appear as dark purple spots, about 20% the diameter of red blood cells.
Platelets contribute to stop bleeding
One major function of thrombocytes / platelets is to contribute to hemostasis: the process of stopping bleeding at the site of interrupted endothelium. They gather at the site and, unless the interruption is physically too large, they plug the hole. Platelets attach, activate and connect to each other forming bridges (fibrin formation / aggregation).
Platelets assist healing & Wound repair
A blood clot is only a temporary solution to stop bleeding; tissue/wound repair is needed in which damaged and dead cells are cleared out. Platelet-derived growth factors are released into the wound that cause the migration and division of cells during the proliferative phase helping the healing process. Local application of these factors in increased concentrations through platelet-rich plasma (PRP) is used as an adjunct in wound healing.
Low platelet concentration
Low platelet concentration is called thrombocytopenia, and is due to either decreased production or increased destruction.
Spontaneous and excessive bleeding can occur because of deficient numbers of platelets or dysfunctional platelets.
Elevated platelet concentration
Elevated platelet concentration is called thrombocytosis. Excessive numbers of platelets, and/or normal platelets responding to abnormal vessel walls, can result in venous thrombosis and arterial thrombosis.
Importance of accurate THROMBOCYTE / platelet count assessment
The precise assessment of the platelet count in whole blood is crucial in clinical hematology as low platelet count may lead to bleeding complications. The normal platelet count is widely determined as 150-400 x 109/L in whole blood and its aberrations have been associated not only with hemostatic and thrombotic diseases but also with cancer and chronic inflammatory diseases. Overall data & various publications suggest that platelet count might be a possible biomarker or prognostic marker for various diseases.
Automated COUNTING of THROMBOCYTES / PLATELETS
Today platelets are either counted manually, which is labor-intensive and time consuming, or automatically using advanced counting devices like flow cytometers or automated hematology analyzers which require serious investments and highly trained people resulting in high cost of operation. These solution require frequent and time-consuming cleaning which makes it labor intensive and not suited for point of care applications. The PC100 Platelet Counter is an easy to use counting device which is accurate and affordable. A dedicated point of care solution within reach of smaller laboratories and point-of-care offices / clinics.
How thrombocytes are counted in whole blood and PRP
Thrombocytes are counted either manually in a counting chamber under the microscope, or automatically. Laboratory hematology analyzers count thrombocytes by impedance or optical (fluorescence) methods as part of a complete blood count; see our comparison of the PC100 vs hematology analyzers. The PC100 uses a patented optical imaging method on a disposable slide and reports the thrombocyte concentration in platelets per nanolitre in about 4 minutes, both for whole blood (20-600 plt/nL) and for platelet rich plasma (250-3600 plt/nL). Background on normal values and reference ranges can be found in the literature, for example in the StatPearls chapter “Physiology, Platelet”.
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