PDW - Blood Analysis

Generality

PDW stands for Platelet Distribution Width, which can be Italianized in "platelet distribution width". This laboratory parameter expresses the degree of variability of the platelet size; consequently, high PDW values ​​indicate a large discrepancy between the volumes of these "cells", while when PDW is low it means that the platelets are uniform in size.
Given this clinical significance, PDW is known as an index of platelet anisocytosis; in fact, anisocytosis refers to the presence in the blood of red blood cells of different sizes.

High PDW values ​​are recorded in myeloproliferative syndromes, but also in the presence of megaloblastic anemia and refractory anemia. This is because thrombopoiesis, that is the synthesis of new platelets, is associated with the production of young platelets, characterized by an increased mean volume (> MPV) compared to older ones.
The clinical significance of PDW must necessarily be evaluated together with other platelet indices, such as total number (PLT), mean volume (MPV) and blood platelet concentration (PCT).
The PDW values ​​can be considered an index of platelet activation, since the volume of platelets tends to increase due to the emission of pseudopodia during the activation of the coagulation processes.

What's this

Platelets (or thrombocytes) are small elements of the blood, with a discoid shape and diameter between 2 and 3 µm, essential for normal coagulation.

Platelets are produced by the bone marrow and are released into the bloodstream; here, they survive in circulation for about 8-10 days, therefore the bone marrow must continuously produce new elements to replace those degraded, consumed and / or lost during bleeding.
The amplitude of distribution of platelet volumes (PDW) is a parameter that indicates how uniform the platelets are in size. Usually, larger cells are relatively young and more recently released from the bone marrow, while small ones may be older and older. remain in circulation for a few more days.

When the PDW values ​​are high, it means that there is a large difference between the platelet volumes, while when the PDW is low, it means that the platelets are uniform in size.

Because it is measured

In blood tests, the PDW index corresponds to the degree of variability in the size of platelets. In other words, the parameter expresses the uniformity or discrepancy in the size of these cells.

PDW may be reported with a complete blood count and is considered by the physician to obtain additional information about platelets and / or the cause of a low or high count.
The magnitude of platelet distribution (PDW) helps diagnose and / or monitor diseases in which these blood cells are not uniform in size, such as haemostasis disorders and myeloproliferative syndromes.