Mean platelet volumeMPV
The average size of your platelets, which hints at how new they are.
Mean platelet volume is the average size of the platelets in a sample. Newly released platelets are larger, so the figure is an indirect clue to how fast the bone marrow is producing them.
It matters mainly in combination with the platelet count. A low count with large platelets suggests the marrow is responding to platelets being consumed or destroyed, while a low count with small platelets points more towards reduced production.
In practice MPV drifts upward the longer a sample sits before analysis, so it is treated as supporting information rather than a standalone result.