Understanding Platelet Count
What is Platelet Count?
A Platelet Count test measures the average number of platelets in the blood. Platelets are tiny, colorless blood cells that play a critical role in blood clotting. This test helps detect or monitor conditions that cause excessive bleeding or clotting. It is often done as part of a complete blood count test that also measures other types of blood cells.
Platelets, also known as thrombocytes, help the blood to clot at an injury site and prevent excessive bleeding. When you have a cut or injury, platelets rush to the site and clump together to form a clot, which helps stop bleeding. Platelets also release substances that promote healing and repair damaged blood vessels. The normal platelet count ranges between 1.5 to 4.5 lacs platelets per microliter of blood.
If your platelet count is too low (thrombocytopenia), it can lead to bleeding problems and difficulty forming clots. A low platelet count can be caused by various factors, including reduced platelet production in conditions like bone marrow failure, increased platelet destruction as seen in ITP (idiopathic thrombocytopenic purpura), or heightened platelet trapping as observed in hypertension. Conversely, if your platelet count is too high (thrombocytosis), it might increase the risk of blood clots. High platelet count may occur due to iron deficiency, infections, or inflammation.
Your doctor may suggest a Platelet Count test if you experience excessive bleeding or bruising symptoms or have conditions that can affect your platelet count. Test results can help the doctor diagnose and monitor various conditions, such as bleeding disorders, certain infections, immune system disorders, and side effects of medications. No special preparation is required for this test; eat or drink as per your daily routine. Inform your doctor if you take any medicines, as they may affect your test results.
Test result ranges are approximate and may differ slightly between labs depending on the methodology and laboratory guidelines. Talk to your doctor about your specific test results. The results will help them determine your medical condition and formulate an overall treatment plan.
What is Platelet Count used for?
A Platelet Count test can be done:
- As part of a complete blood count test to monitor your overall health.
- In case of signs and symptoms of bleeding disorders, such as easy bruising and prolonged bleeding.
- To detect and monitor clotting disorders.
- To detect or monitor diseases affecting platelets, such as dengue or inflammatory diseases.
- Before surgery, if you have a personal or family history of bleeding disorders.
- To monitor platelet count if you are taking blood-thinning medicines, underwent chemotherapy treatment, or a platelet transfusion procedure.
What does Platelet Count measure?
A Platelet Count test measures the average number of platelets in the blood. Platelets are disk-shaped tiny cells originating from large cells known as megakaryocytes, which are found in the bone marrow. After the platelets are formed, they are released into the blood circulation. Their average life span is 7-10 days.
Platelets help stop the bleeding, whenever there is an injury or trauma to a tissue or blood vessel, by adhering and accumulating at the injury site and releasing chemical compounds that stimulate the gathering of more platelets. A loose platelet plug is formed at the site of injury and this process is known as primary hemostasis. These activated platelets support the coagulation pathway that involves a series of steps, including the sequential activation of clotting factors; this process is known as secondary hemostasis. After this step, there is a formation of fibrin strands that form a mesh incorporated into and around the platelet plug. This mesh strengthens and stabilizes the blood clot so that it remains in place until the injury heals. After healing, other factors come into play and break the clot down so that it gets removed. In case the platelets are not sufficient in number or not functioning properly, a stable clot might not form. These unstable clots can result in an increased risk of excessive bleeding.
Interpreting Platelet Count results
The normal platelet count ranges from 150,000 to 450,000 platelets per microliter of blood.
Answers to Patient Concerns & Frequently Asked Questions (FAQs) about Platelet Count
Frequently Asked Questions about Platelet Count
Q. Why is a Platelet Count test done?
Q. How is a Platelet Count test done?
Q. What happens if my platelet count is high?
Q. What all conditions can a Platelet Count test detect?
Q. What are the functions of platelets?
Q. What are the signs and symptoms associated with low platelet count ?
Book Platelet Count at-home
- Platelets [Internet]. Rochester, NY: University of Rochester Medical Center; [Accessed 07 Feb. 2023]. Available from: https://www.urmc.rochester.edu/encyclopedia/content.aspx?contenttypeid=167&contentid=platelet_count
- Heber S, Volf I. Effects of Physical (In)activity on Platelet Function. Biomed Res Int. 2015;2015:165078. [Accessed 07 Feb. 2023]. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4628769/
- Jurk K, Kehral B. Platelets: Physiology and Biochemistry. Semin Thromb Hemost. 2005; 31(4):381-392. [Accessed 07 Feb. 2023]. Available from: https://www.thieme-connect.com/products/ejournals/html/10.1055/s-2005-916671
- Park Y, Schoene N, Harris W. Mean platelet volume as an indicator of platelet activation: methodological issues. 2002; 13(5-6):301-306. [Accessed 07 Feb. 2023]. Available from: https://www.tandfonline.com/doi/abs/10.1080/095371002220148332
- O'Brien JR, Oxon DM, FCPath. Effects of salicylates on human platelets. The Lancet. 1968 Apr 13;291(7546):779-783. [Accessed 07 Feb. 2023]. Available from: https://www.sciencedirect.com/science/article/abs/pii/S0140673668922289
- Frelinger III AL, Grace RF, Gerrits AJ, et al. Platelet function tests, independent of platelet count, are associated with bleeding severity in ITP. Blood. 2015 Aug 13;126(7):873-879. [Accessed 07 Feb. 2023]. Available from: https://ashpublications.org/blood/article/126/7/873/34465/Platelet-function-tests-independent-of-platelet
- Platelet count [Internet]. California, San Francisco: The Regents of The University of California; [accessed 07 Feb. 2023]. Available from: https://www.ucsfhealth.org/medical-tests/platelet-count