Understanding the System Principles
3-11
3.5.4 Derivation of PLT-Related Parameters
PLT
PLT (10
9
/L) is measured directly by counting the platelets passing through the aperture.
MPV
Based on the PLT histogram, this analyzer calculates the mean platelet volume (MPV, fL).
PDW
Platelet distribution width (PDW) is the geometric standard deviation (GSD) of the platelet
size distribution. Each PDW result is derived from the platelet histogram data and is reported
as 10 (GSD).
PCT
This analyzer calculates the PCT as follows and express it in %.
Where the PLT is expressed in 10
9
/L and the MPV in fL.
PLT Histogram
Besides the parameters mentioned above, this analyzer also presents a PLT histogram,
whose x-coordinate represents the cell volume(fL)and y-coordinate represents the number
of the cells. The histogram is presented in the Analysis Result area of the “Count” screen
when the analysis is done. You can also review the histograms of the stored patient results
(see Chapter 7 Reviewing Sample Results).
The two discriminators of the PLT histogram can be adjusted in case you are not satisfied
with the result. Note that you cannot adjust them if the PLT result is less than 10 or out of the
operating range.
10000
MPVPLT
PCT
×
=