Platelet Count
The number of platelets, the cell fragments that form clots to stop bleeding.
| Typical reference range | 140–400 x10E3/uL |
Ranges vary by laboratory, method, age and sex: always use the range printed on your own report. Why labs differ.
What it measures
Platelets are produced from megakaryocytes in the bone marrow, regulated by the hormone thrombopoietin from the liver. They live 7-10 days and about one-third are stored in the spleen.
Why it matters
Platelet count assesses bleeding and clotting risk and can reveal marrow, liver, spleen or inflammatory problems.
What a high result can mean
High counts (thrombocytosis) most often reflect a reactive process: iron deficiency, inflammation, infection, recent surgery or bleeding, or after splenectomy. Persistently very high counts can indicate essential thrombocythemia or other myeloproliferative disorders.
What a low result can mean
Low counts (thrombocytopenia) can result from viral infections, immune thrombocytopenia, medications (heparin, some antibiotics), alcohol, liver disease with an enlarged spleen, B12/folate deficiency, pregnancy and marrow disorders. Clumping in the EDTA tube can produce a falsely low count (pseudothrombocytopenia).
What affects the result
If unexpectedly low, a repeat in a citrate tube or a smear can rule out clumping. Iron deficiency commonly raises platelets. Interpret with MPV and the rest of the CBC.
Units and conversion
Usually reported in x10E3/uL.
- From K/uL: multiply by 1 to get x10E3/uL
- From Thousand/uL: multiply by 1 to get x10E3/uL
- From 10^3/uL: multiply by 1 to get x10E3/uL
- From x10^9/L: multiply by 1 to get x10E3/uL
- From 10*3/uL: multiply by 1 to get x10E3/uL
- From x10E9/L: multiply by 1 to get x10E3/uL
- From G/L: multiply by 1 to get x10E3/uL
Also called on lab reports
Platelets, PLT, Thrombocytes, Platelet, Platelet Count, Automated
Related tests: Platelets
This page is educational and does not replace advice from a healthcare professional.