Understanding Low MPV Results

"MPV" stands for mean platelet volume and is a measure of the size of your platelets. Platelets, or thrombocytes, are fragments of cells in the blood. They help the blood to clot and repair damaged blood vessel walls in order to stop or prevent bleeding. MPV is often tested as part of a platelet count measuring the number of platelets in a sample of blood, or as part of a complete blood count (CBC).

This article will review low MPV results and what they mean.

What Is MPV?

The mean platelet volume is the measure of the size of the platelets in the blood. The size of the platelets is reported as femtoliters, and a normal MPV is 8–12 femtoliters. The MPV also is an indicator of how active platelets are.

Obtaining an MPV can be helpful when looking into the causes of platelet disorders such as thrombocytopenia, or low platelet counts, or thrombocytosis, which is an elevation in platelet counts.

Low MPV Test Results

To test the MPV, a sample of blood is taken from a vein, most often in the hand or arm. The blood is collected into a sample tube and is then analyzed by a specialized machine.

A report showing that the MPV is less than 8 femtoliters means the platelets are small in size. Small platelets are generally older platelets, as new platelets that are released into the circulation are typically larger.

Low MPV and Platelet Count

When evaluating the MPV, it is important to know that an MPV level on its own is not diagnostic of anything in particular. Instead, the reading needs to be looked at in the context of the total number of platelets compared to their size.

The MPV can decrease despite the number of platelets that are found. 

Low MPV and Low Platelet Count

When thrombocytopenia (low platelet count) is present with a low MPV, it can indicate that the low platelet counts are due to the bone marrow not functioning properly. An abnormally functioning bone marrow can be found in conditions such as aplastic anemia, when your bone marrow stops producing enough blood cells.

Low MPV and High Platelet Count

A higher-than-normal platelet count (thrombocytosis) can be caused by a variety of factors. However, when thrombocytosis occurs with a low MPV, it is likely due to a reaction to something else, such as inflammation, infection, or cancer. 

Low MPV and Normal Platelet Count

The size of the platelets can be small, resulting in a low MPV, even if the platelet count is normal. This is often the case in people living with kidney disease. It can also be seen as a side effect of some medications.

Causes of Low MPV

Multiple conditions can cause a low MPV. These conditions include:

• Bone marrow failure
• Aplastic anemia
• Inflammation or autoimmune diseases
• Infections
• Cancer
• Splenomegaly (enlarged spleen)

A Word From Verywell

When reviewing blood tests, the MPV is only one of many blood tests performed. The MPV in and of itself does not diagnose any specific disease or disorder but is looked at in combination with other blood tests to come up with a diagnosis. If you have any questions about any of your blood tests, you should check with your healthcare provider for answers and clarification.