What causes an elevated Mean Platelet Volume (MPV)?

Causes of Elevated Mean Platelet Volume (MPV)

Elevated Mean Platelet Volume (MPV) is primarily caused by conditions that involve increased platelet turnover or destruction, myeloproliferative disorders, and certain inflammatory or metabolic conditions. 1

Primary Causes

• Myeloproliferative disorders are major causes of elevated MPV, including:

  • Essential thrombocythemia
  • Polycythemia vera
  • Primary myelofibrosis
  • Chronic myeloid leukemia 1, 2

• Platelet destruction conditions consistently show elevated MPV values:

  • Immune thrombocytopenia (ITP)
  • Disseminated intravascular coagulation (DIC)
  • Thrombotic thrombocytopenic purpura (TTP) 3, 4

Secondary Causes

• Hematologic disorders:

  • Post-hemorrhagic states
  • Hemolytic anemia
  • Post-splenectomy or functional hyposplenism
  • Rebound thrombocytosis after treatment of thrombocytopenia 2

• Metabolic and inflammatory conditions:

  • Iron deficiency anemia
  • Heterozygous thalassemia 4
  • Obesity (associated with increased inflammatory cytokines) 5
  • Diabetes mellitus 5
  • Metabolic syndrome 5

• Cardiovascular conditions:

  • Acute myocardial infarction
  • Stroke
  • Atherosclerotic disease 6, 5

Physiological Causes

• Pregnancy and hormonal influences can cause temporary elevation in MPV 2
• Exercise-induced changes may transiently increase MPV 2
• Aging is associated with gradually increasing MPV values 1

Diagnostic Value of MPV

• An MPV value ≥8.8 fL has been identified as a useful cut-off for distinguishing over-destructive thrombocytopenia from underproductive causes (sensitivity 77%, specificity 89%) 3

• MPV serves as an indicator of platelet activation and reactivity, with larger platelets being more hemostatically active and producing more prothrombotic factors 7, 5

• When interpreting MPV, it's important to consider both the platelet count and MPV together, as this combination provides more diagnostic information than either parameter alone 4

Clinical Significance and Monitoring

• Elevated MPV is an independent risk factor for cardiovascular events, including myocardial infarction, stroke, and restenosis after coronary angioplasty 6, 5

• Serial measurements of MPV are more valuable than isolated readings to establish chronicity and monitor disease progression 1

• In patients with myeloproliferative disorders like polycythemia vera, monitoring MPV alongside other parameters helps assess disease activity and thrombotic risk 8, 1

Important Caveats

• Pre-analytical variables can significantly affect MPV measurement:

  • Time between blood collection and analysis (MPV increases with time in EDTA tubes)
  • Temperature (exposure to 4°C increases MPV while 37°C decreases it)
  • Type of anticoagulant used 7

• In conditions with increased hematocrit (like polycythemia vera), standard amounts of anticoagulant with reduced plasma volume can affect platelet parameters 2

• MPV should always be interpreted in clinical context and alongside other laboratory parameters, particularly the platelet count 4