Plateletcrit
Plateletcrit (PCT) is the fraction of your blood volume occupied by platelets, calculated from your platelet count and mean platelet volume. It's the platelet equivalent of hematocrit for red cells.
Plateletcrit combines how many platelets you have with how big they are into a single measure of total platelet mass. It can offer a fuller sense of platelet status than the count alone in some situations.
An above-range plateletcrit reflects a larger overall platelet mass, which can occur when the platelet count is elevated, whether reactively (from inflammation or infection) or, less commonly, from a marrow condition. It's read together with the platelet count and MPV.
A below-range plateletcrit reflects a smaller total platelet mass, typically mirroring a low platelet count.
Reference ranges are analyzer-specific, so your lab's stated range is the best reference. Interpret it with your clinician alongside your platelet count and MPV.
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.