Platelets are essential for blood clotting. Learn what your count means and when abnormal levels need attention.
Platelets (also called thrombocytes) are tiny blood cells produced in your bone marrow. Their primary job is to help your blood clot when you're injured — they rush to the site of damage, stick together, and form a plug to stop bleeding.
Unlike red and white blood cells, platelets are actually fragments of larger cells called megakaryocytes. Each megakaryocyte produces about 1,000-3,000 platelets. Your body produces roughly 100 billion platelets daily to maintain normal levels.
According to the National Heart, Lung, and Blood Institute (NHLBI), a normal platelet count ranges from 150,000 to 400,000 platelets per microliter (μL) of blood.
Healthy platelet count for proper blood clotting
Slightly low, usually no bleeding risk
May bruise easily, bleeding risk with surgery
Significant bleeding risk, requires medical attention
Elevated platelets, may increase clotting risk
Select your platelet value for a detailed explanation of what it means and what to do next.
Thrombocytopenia means your platelet count is below 150,000/μL. The Mayo Clinic classifies it by severity:
| Severity | Count | Risk |
|---|---|---|
| Mild | 100,000-150,000/μL | Usually no symptoms |
| Moderate | 50,000-100,000/μL | Easy bruising, surgery risk |
| Severe | <50,000/μL | Spontaneous bleeding risk |
Bone marrow issues (leukemia, aplastic anemia, myelodysplasia), chemotherapy, radiation, heavy alcohol use, B12/folate deficiency, viral infections (HIV, hepatitis C).
Immune thrombocytopenia (ITP), medications (heparin, sulfa drugs, quinine), autoimmune diseases (lupus), TTP, HUS, DIC, severe infections.
Enlarged spleen (from liver disease, infections, cancers) can trap up to 90% of platelets. Normal spleen holds only 30%.
Gestational thrombocytopenia affects 5-10% of pregnancies. Usually mild and resolves after delivery. HELLP syndrome is more serious.
Thrombocytosis means your platelet count exceeds 450,000/μL. According to the Cleveland Clinic, there are two main types:
Most common (~85%). Caused by infection, inflammation, iron deficiency, cancer, surgery, or splenectomy. Platelets usually <1,000,000/μL. Rarely causes clotting problems.
Less common (~15%). Bone marrow disorder (essential thrombocythemia, polycythemia vera). Can cause both clotting and bleeding. Requires hematology evaluation.
Upload your CBC results and monitor your platelet trends. Catch changes early and share with your doctor.
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