Platelet Distribution Width (PDW)
Haematology marker
PDW
Platelet Distribution Width (PDW)
A measure of the variability in platelet size (the width of the platelet size distribution). A higher PDW means platelets vary more in size, which reflects differences in platelet production and turnover. It is reported automatically as part of the platelet indices on a full blood count.
PED Notes
A minor platelet index, most useful read alongside platelet count and mean platelet volume (MPV) rather than alone. A raised PDW indicates a more heterogeneous, often more active platelet population and tends to move with MPV. It is not directly affected by AAS, but because enhanced athletes carry elevated cardiovascular risk (erythrocytosis, blood pressure, lipid shifts), platelet indices are occasionally noted as part of the broader thrombotic-risk picture. On its own it is rarely actionable.
When high
When high (>17 fL):
- Reflects greater variability in platelet size, usually from increased platelet turnover; commonly moves together with a raised MPV
- Interpret with the platelet count and MPV: high PDW with a low platelet count suggests active platelet destruction or consumption (investigate), whereas high PDW with a normal count is often benign
- Some studies associate raised platelet indices with a more prothrombotic state; in an enhanced athlete with concurrent erythrocytosis or hypertension, manage overall cardiovascular risk (hydration, blood pressure, consider haematocrit management) rather than the PDW value itself
- No supplement targets PDW directly
When low
When low (<9 fL):
- A low PDW indicates a more uniform platelet population and is generally not clinically significant
- No specific intervention is needed; interpret alongside the platelet count and MPV
Educational information, not medical advice. Nothing here is a prescription or a treatment plan, and it does not account for your history, medications or conditions. Use it to ask better questions: bring it to your doctor and decide together. Full disclaimer.
History Chart
Reading History
Frequently Asked Questions
Reference Ranges
Standard Range