Thrombocytes - Platelets

Definition of Thrombocytes - Platelets

Platelets, artwork. Credit: Sciepro / Getty Images

Definition of Thrombocyte - Platelet

Thrombocyte is another word for platelet, the blood cell that is responsible for normal blood clotting. The root thrombo- means clot and you will see it used with diseases and conditions that affect the platelets and blood clotting.

What Do Normal Platelets (Thrombocytes) Do?

Platelets originate from cells known as megakaryocytes, which are found in the bone marrow.

They are important for normal blood clotting. When there is a break or cut in one of your blood vessels, they adhere to the site, send out chemical signals for more help, and connect to each other to form a plug. The rest of the coagulation cascade can then add fibrin to hold the clot together. You often see this happening if you cut your finger and it stops bleeding, but it also happens in blood vessels throughout your body.

If there are not enough platelets, the risk of uncontrolled or prolonged bleeding increases. When there are too many platelets in the blood, it may lead to abnormal blood clot formation, a serious and life-threatening condition.

Aspirin and some non-steroidal anti-inflammatory drugs inhibit platelet function, which is why you may be asked to stop using them for a few days before a surgery or procedure.

What Does Your Platelet Count Mean?

Looking at the numbers, size, and health of platelets (thrombocytes) is a part of a Complete Blood Count (CBC) test.

The platelet count is an important number for your doctor to know before and after surgery in order to predict bleeding and clotting problems. It is also an important number during chemotherapy and radiation therapy as these can inhibit the production of platelets in the bone marrow.

  • Platelet Count (PLT): Normal range is 150-450 103/microliter or 150,000 - 450,000 per microliter.
  • Mean platelet volume (MPV): the average size of the platelets. Younger platelets are larger than older ones, so an elevated number means you are producing and releasing them rapidly while a low number means altered production in the bone marrow.
  • Platelet distribution width (PDW): the variation in size of the platelets, which can indicate conditions that affect the platelets.

Platelet function tests may also be performed if there are symptoms or potential for excessive bleeding and to monitor anti-platelet medications.

Thrombocytopenia - Low Platelet Count

When you undergo chemotherapy or radiation therapy, you may have a low platelet count due to the effects on the blood-producing cells in your bone marrow. A platelet count below 20,000 per microliter is a life-threatening risk as spontaneous bleeding may occur and be hard to stop. At that level, you may be given a platelet transfusion.

Other conditions that can cause thrombocytopenia include autoimmune disorders, viral infections, drugs, heparin antibodies, leukemia, lymphoma, aplastic anemia, chronic bleeding, sepsis, cirrhosis, disseminated intravascular coagulation, and toxic exposures.

Thrombocytosis - High Platelet Count

High platelet counts can be seen in cancer, especially with gastrointestinal cancer as well as lymphoma, lung, ovarian and breast cancer. This is thought to be due to the inflammation associated with the malignancy stimulating the production of platelets in the bone marrow.

Other conditions that may show thrombocytosis include anemia, inflammatory conditions such as rheumatoid arthritis and IBD, tuberculosis, and use of oral contraceptives. If you've had your spleen removed, you may also have a high platelet count. A temporary increase in the platelet count can happen after major surgery or blood loss and during recovery from vitamin B12 and folate deficiency.


Platelet Count, Lab Tests Online, American Association for Clinical Chemistry. Accessed 2/16/2016

Ioannis A Voutsadakis. "Thrombocytosis as a prognostic marker in gastrointestinal cancers." World J Gastrointest Oncol. 2014 Feb 15; 6(2): 34–40.

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