The number of platelets in the blood. Advanced liver failure causes platelet counts to drop, increasing the risk of bleeding (see ‘platelets').
Counts below 100,000/ml are significant. Platelets can be counted directly, or numbers can be estimated from the blood smear (5 per oil-immersion field). Decreased platelet numbers (thrombocytopenia) occur with disseminated intravascular coagulation, bone marrow depression, autoimmune hemolytic anemia, systemic lupus erythematosus and severe hemorrhage. Thrombocytosis (increased platelet numbers) is caused by excess bleeding (from trauma, blood sucking parasites or neoplasia), iron deficinecy anemia and myeloproliferative syndromes.
Platelets are tiny fragments of cells, made in the bone marrow, that circulate in the blood. They function to stop bleeding by sticking together and forming plugs (blood clots). Low platelet levels predispose individuals to excessive bleeding. High platelet counts may occur in pregnancy or after strenuous exercise.
a blood test done by counting the number of platelets in a known volume of blood
The number of platelets in a blood sample.
The calculated number of platelets in a volume of blood, usually expressed as platelets per cubic millimeter (cmm) of whole blood. Platelets are the smallest cell-like structures in the blood and are important for blood clotting and plugging damaged blood vessels. Platelet counts are usually done by laboratory machines that also count other blood elements such as the white and red cells. They can also be counted by use of a microscope. Normal platelet counts are in the range of 150,000 to 400,000 per microliter (or 150 - 400 x 109 per liter). These values many vary slightly between different laboratories.
Measures the number of platelets in a drop of blood. Platelet counts increase during strenuous activity and certain conditions called myeloproliferative disorders: infections, inflammations, malignancies, and when the spleen has been removed. Platelet counts decrease just before menstruation. Normal values range from 150,000 to 400,000 per microliter. A count below 50,000 can result in spontaneous bleeding; below 5,000, patients are at risk of severe life-threatening bleeding.
The number of platelets in the blood sample.
The number of platelets iin a blood sample.