Platelet Indices

This is the automated calculation of the platelets indices, which consists of the following:

1. Mean platelet volume (MPV).
2. Plateletcrit (Pct).
3. Platelet distribution width (PDW).

What are the indications for Platelet Indices?

1. Platelet indices are potentially useful markers for the early diagnosis of thromboembolic diseases.
2. MPV and PDW help discriminate causes of thrombocytopenia as hypoproductive or hyper-destructive, like immune thrombocytopenic purpura.
3. An increase in both mean platelet volume (MPV) and platelet distribution width (PDW) due to platelet activation was suggested due to:
   1. Platelet swelling.
   2. Pseudopodia formation.
   3. MPV and PDW are simple platelet indices that increase during platelet activation.

Mean Platelet Volume (MPV)

How will you define MPV?

1. MPV represents the average size of the platelets.
2. It is determined from the arithmetic mean of the platelets histogram provided by the hematology analyzer.

3. MPV is a machine-calculated measurement of the average size of platelets found in blood and is typically included in blood tests as part of the CBC.
4. Primarily with thrombocytopenia when it is due to Impaired production, as in aplastic anemia.
5. MPV is very useful in the case of thrombocytopenia.

What is the source of error in calculating MPV?

• Major source of error is fragmented RBCs.

When will it be MPV higher?

1. When platelets are destroyed.
2. This may be seen as an inflammatory bowel disease.
3. In immune thrombocytopenic purpura (ITP).
4. In various thrombocytopenias.
5. In the case of increased-sized platelets like myeloproliferative diseases and May-Hegglin syndrome.
6.  Also seen in Bernard-Soulier syndrome, where the platelets are large.
7. It may also be related to preeclampsia and recovery from transient hypoplasia.

When will there be Low MPV values?

1. It will be associated with bleeding.
2. The release of immature platelets to the circulation, which is larger in size, leads to raised MPV.
3. In the case of ineffective platelet formation in the bone marrow, as their size is smaller, there is low MPV

What is the normal MPV?

• It ranges from 7.4 to 10.4 fL

Plateletcrit (Pct)

How will you define plateletcrit (Pct)?

1. Plateletcrit measures the total mass as a percentage of the volume occupied in the blood.
2. Plateletcrit is an effective screening tool for detecting quantitative platelet abnormalities.
3. Normal platelet count has a Plateletcrit within the 0.20 to 0.36% range.

What is the normal plateletcrit (Pct)?

1. Plateletcrit- 0.22 to 0.23%.
2. Sensitivity and specificity for detection of :
   1. Thrombocytopenia at the Plateletcrit cutoff range of 0.20 – 0.36% is 97% and 80%.
   2. Thrombocytosis is 94% and 98%.

Platelet distribution width (PDW)

How will you define Platelet distribution width (PDW)?

1. It is the measure of variability in the size of platelets.

What are the important facts about PDW?

1. PDW is a simple, practical, and specific marker of activation of coagulation.
2. PDW is a more specific marker of platelet activation since it does not increase during simple platelet swelling.
3. PDW has received attention due to its usefulness in distinguishing between reactive thrombocytosis and thrombocytosis associated with a myeloproliferative disorder.
4. The determination of the PDW reference range is fundamental.
5. Mean platelet volume (MPV) and platelet distribution width (PDW) are helpful in the differential diagnosis of aplastic anemia and idiopathic thrombocytopenic purpura.
6. An increased PDW is an indication of the anisocytosis of platelets.

What is the normal Platelet distribution width (PDW)?

1. Standard PDW ranges from 9 to 14 fL.

What is the outcome of platelet indices?

Questions and answers: