Low MPV in a blood test means a person's mean platelet volume is lower than normal, according to WebMD. Mean platelet volume refers to the average size of the platelets in the blood.
Low mean platelet volume is associated with chronic kidney failure, widespread infection and the use of toxic drugs. In most cases, young platelets have a larger volume than older platelets that have been circulating for several days, according to experts from the American Association of Clinical Chemistry . If someone has a low MPV, it could mean they are not producing as many new platelets as they should be. The person's physician may order additional tests to determine why the mean platelet volume is lower than expected.