Platelet Distribution Width
Platelet distribution width (PDW) measures how much your platelets vary in size. A higher value means your platelets differ more from one another in size.
Just as red cell distribution width describes variation among red cells, PDW describes variation among platelets, offering an extra detail about platelet production and turnover. It's a supporting measure rather than a stand-alone diagnostic number.
An above-range PDW indicates a wider mix of platelet sizes, which can accompany active platelet production or certain platelet and inflammatory conditions. It's interpreted alongside your platelet count and MPV rather than in isolation.
A below-range or normal PDW suggests your platelets are fairly uniform in size, which on its own is generally not a concern.
Reference ranges vary by analyzer, so there isn't a single universal target; your lab's range is the reference point. Let your clinician interpret PDW together with the rest of your platelet indices.
Sources
Educational context only, not medical advice or a diagnosis. Reference ranges vary by lab, age and sex; always discuss your results with a clinician.