Posted September 13, 2022 by Anusha ‐ 4 min read

Platelets are the smallest component of your blood that control bleeding. Platelets cluster together to form a clot and prevent bleeding at the site of an injury.

What are platelets?

Platelets, also called thrombocytes, are tiny components of your blood that help with clotting. Platelets are your body’s natural bandage to stop bleeding.

What are the functions of platelets?

Your platelets function to stop bleeding. During an injury, your platelets will cluster together at the site of the wound to act as a plug, sealing blood vessels in a process called clotting to prevent excess blood from leaving your body.

Where are platelets located?

  • Platelets are components in your blood and spleen. Whole blood consists of plasma, red and white blood cells and platelets.

  • Since platelets are the lightest component of whole blood, they are pushed to the walls of your blood vessels, allowing plasma and blood cells to flow through the center, which helps platelets reach injury quickly to prevent bleeding.

What do platelets look like?

  • Platelets are small, colorless fragments of cells.

  • Platelets form in the shape of a plate, which is where they get their name.

  • Proteins on the exterior of your platelet walls are sticky to help it adhere to your blood vessels. When actively clotting, platelets extend filaments that resemble legs on a spider.

  • These legs make contact with the broken blood vessel and other clotting factors to seal the damage and stop the bleeding.

How many platelets are present in the blood?

  • Platelets and white blood cells make up 1% of your whole blood along with plasma (55% total volume) and red blood cells (44% total volume).

  • There is about one platelet for every 20 red blood cells in your body.

  • In a single drop of blood, there are tens of thousands of platelets.

Where are platelets made?

Platelets form in the soft tissue of your bones (bone marrow). The largest cells in your bone marrow (megakaryocytes) make platelets.

What is a normal platelet count?

  • During a complete blood count test (CBC), your healthcare provider will remove a sample of your blood from your vein to test how many white blood cells, red blood cells and platelets are in the sample.

  • A normal platelet count for adults ranges from 150,000 to 450,000 platelets per microliter of blood.

  • Any count above 450,000 or below 150,000 would be risk factors for platelet-related conditions.

What are common conditions that affect platelets?

There are two conditions that are the result of an abnormal platelet count:

  • Thrombocytopenia: Low platelet count can lead to bruising and excessive bleeding.

  • Thrombocytosis: High platelet count can lead to abnormal blood clotting.

What causes my platelet count to be too high?

Abnormal cells in your bone marrow cause your platelet count to be too high. The reason for abnormal cell formation is unknown.

What causes my platelet counts to be too low?

Potential causes for low platelet count include:

  • Alcohol use disorder.

  • Viral (hepatitis C, HIV) or bacterial infections.

  • Autoimmune diseases.

  • Bone marrow diseases (anemia) or cancer.

  • Enlarged spleen.

  • Chemical exposure.

  • Side effect of a medication or treatment.

  • Kidney infections or dysfunction.

What happens if platelet counts are low?

  • If your platelet count is too low (thrombocytopenia), you won’t have enough platelets to clot a wound. In the event of an injury, you may bleed too much and it could be difficult to stop.

  • Low platelet count can lead to excessive blood loss, hemorrhaging and internal bleeding, which could be life-threatening.

  • Severe cases of bleeding inside of your body and underneath your skin as a result of not having enough platelets is a bleeding disorder called immune thrombocytopenia (ITP).

  • This condition causes tiny red and purple dots on your skin (petechiae) that resembles a rash along with bruises from blood vessels under your skin (purpura).

  • Treatment to increase your platelet count improves your prognosis for ITP.

What happens if platelet counts are high?

If your platelet count is too high, platelets will stick together and cause unnecessary clotting in your blood vessels. Blood clots could lead to heart attack and stroke.

What are symptoms of platelet conditions?

Common symptoms of platelet conditions include:

  • Bruising.

  • Frequent nose bleeds or bleeding gums in your mouth.

  • Blood in your stool or urine.

  • Internal bleeding.

  • Excessive bleeding from small wounds.

  • Heavy menstrual periods.

  • Muscle, joint pain, tingling in hands/feet, leg swelling.

  • Severe headaches, dizziness or weakness.

What tests check the health of my platelets?

Tests that check the health of your platelets include:

  • Complete blood count: A blood test identifies how many blood cells and platelets are circulating throughout your body. This test evaluates your overall health and can detect a number of diseases and conditions.

  • Platelet count: Your healthcare provider will use a sample of your blood from a complete blood count test to identify how many platelets are in the sample.

  • Bone marrow biopsy: Your healthcare provider removes a sample of your bone marrow to examine the health of your cells where platelets form.

Common treatments for platelet conditions include:

  • Receiving blood transfusions.

  • Taking steroids or antibiotics.

  • Undergoing surgery to remove your spleen (splenectomy).

  • Taking a low dose of aspirin regularly.

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