Unit Converter
MPV – Mean Platelet Volume

SI UNITS (recommended)

CONVENTIONAL UNITS

(Average Size of Platelets - Marker of Platelet Production, Activation & Bone Marrow Activity)

Synonyms

  • MPV
  • Mean platelet volume
  • Platelet size index
  • Average platelet volume
  • Platelet cell volume

Units of Measurement

  • fL (femtoliters)
  • µm³ (cubic micrometers)
  • cu µm
  • cubic µm

Key Unit Conversion

1 fL=1 µm3=1 cubic µm1\ \text{fL} = 1\ \text{µm}^3 = 1\ \text{cubic µm}1 fL=1 µm3=1 cubic µm

Therefore:

  • 7 fL = 7 µm³
  • 12 fL = 12 µm³

All listed units are numerically identical.

Description

MPV measures the average volume (size) of circulating platelets and reflects:

  • Platelet production
  • Platelet activation
  • Bone marrow megakaryocyte activity

Larger platelets are usually younger and more active.
Smaller platelets usually indicate reduced production or marrow suppression.

MPV is part of the standard CBC and platelet indices, interpreted along with:

  • Platelet count
  • PDW (platelet distribution width)
  • P-LCR (large cell ratio)

Physiological Role

MPV is a diagnostic index, not a biological substance, but correlates with:

  • Thrombopoiesis (megakaryocyte function)
  • Platelet activation status
  • Severity of thrombocytopenia or marrow response

Platelets with higher MPV contain more granules and are more reactive.

Clinical Significance

HIGH MPV

(Usually > 10–12 fL)

Causes - Increased Production / Destruction

  1. Immune Thrombocytopenic Purpura (ITP)
    • Classic: low platelet count + high MPV (large young platelets)
  2. Recovery Phase of Thrombocytopenia
    • After bone marrow recovery
    • Post-chemotherapy, post-viral infection
  3. Inflammation / Infection
     Elevated due to platelet activation.
  4. Myeloproliferative Neoplasms (MPN)
    • ET, PV, early myelofibrosis
  5. Hyperthyroidism
  6. Cardiovascular Risk
     High MPV associated with:
    • MI
    • Stroke
    • Unstable angina
    • Diabetes mellitus

LOW MPV

(Usually < 7 fL)

Causes - Reduced Production

  1. Aplastic Anemia
  2. Bone Marrow Failure
  3. Chemotherapy / Radiation
  4. Wiskott–Aldrich Syndrome
    • Classic: low platelets + very low MPV
  5. Chronic Kidney Disease
  6. Hypothyroidism
  7. Nutritional Deficiencies (B12, folate)

Clinical significance

Low MPV = decreased or ineffective platelet production.

Reference Intervals

(Tietz 8E + WHO + Mayo + ARUP)

Adults

  • 7 – 12 fL

Children

  • 7 – 11.5 fL

Neonates

  • Slightly higher values possible due to immature thrombopoiesis.

Patterns & Interpretation

Platelet CountMPVInterpretation
↓ Platelets + ↑ MPVIncreased destruction (e.g., ITP)
↓ Platelets + ↓ MPVProduction failure (bone marrow disease)
Normal platelets + ↑ MPVPlatelet activation (inflammation/CVD)
Normal platelets + ↓ MPVChronic bone marrow suppression

Diagnostic Uses

1. Evaluate Thrombocytopenia

  • High MPV → destruction
  • Low MPV → decreased production

2. Cardiovascular and Thrombotic Risk

Higher MPV associated with more reactive platelets.

3. Monitor Bone Marrow Recovery

MPV rises early when marrow restarts platelet production.

4. Distinguish Disorders

  • ITP vs aplastic anemia
  • MPN vs secondary thrombocytosis

5. Inflammatory Disease Activity

High MPV in:

  • IBD
  • Sepsis
  • Autoimmune diseases

Analytical Notes

  • EDTA samples may show platelet swelling → MPV may rise with time.
  • Optimal measurement within 1–2 hours of collection.
  • Cold agglutinins and giant platelets can cause analyzer errors.
  • Always interpret MPV with platelet count and smear review.

Clinical Pearls

  • MPV is inversely related to platelet count in many conditions.
  • High MPV + thrombocytopenia strongly suggests ITP.
  • Very low MPV (<6 fL) → think Wiskott–Aldrich syndrome or marrow failure.
  • High MPV is linked to higher cardiovascular risk in diabetes and smokers.
  • MPV may help differentiate reactive thrombocytosis (normal MPV) from MPN (usually high MPV).

Interesting Fact

Platelets with high MPV contain more dense granules, making them more hemostatically active - contributing to increased thrombotic risk.

References

  1. Tietz Clinical Chemistry & Molecular Diagnostics, 8th Edition - Hematology
  2. WHO Hematology Reference Standards
  3. Mayo Clinic Laboratories - Platelet Indices
  4. ARUP Consult - CBC Interpretation
  5. MedlinePlus / NIH - Platelet Tests

Last updated: January 26, 2026

Reviewed by : Medical Review Board

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