Mean platelet volume

Ranges depend heavily on the analyser (some print 7 to 12 or 9 to 13); use the range your lab printed.

The mean platelet volume is the average size of the platelets, in femtolitres. Young platelets are larger than old ones, so a high MPV usually means the bone marrow is making platelets quickly, and a low one that it is making them slowly.

It is printed automatically with the platelet count rather than requested on its own. Doctors use it, together with the count, to work out whether a low platelet count is due to platelets being used up or destroyed (large platelets) or to the marrow not making enough (small platelets).

• Conditions where platelets are destroyed or used up, so the marrow makes young large ones
• Recovery after chemotherapy or a bone marrow suppressing illness
• An overactive thyroid
• Some bone marrow conditions
• Some inherited platelet conditions

• Conditions where the bone marrow makes fewer platelets
• Some medicines that suppress the marrow
• Some inherited platelet conditions
• Long-term inflammatory illness

• Platelets swell in the sample tube over the first few hours, so a sample analysed late reads higher
• Different analysers give different values, so it is not comparable between laboratories
• Some analysers do not print it at all when the count is very low or platelets have clumped

No fasting needed. Read alongside the platelet count, and only comparable when measured on the same analyser.

Written by a UK consultant physician. Typical UK adult reference ranges; your laboratory's own printed range takes precedence.