FUNCTIONAL DESCRIPTIONS
Sysmex SF-3000 Operator's Manual -- Revised September 1995 10-13
7.2 PLT Particle Size Distribution
The PLT particle size distribution analysis is performed by using three discriminators.
The lower discriminator (LD) is adjusted automatically in the 2-6 fL (femtoliter) size
range; an upper discriminator (UD), in the 12-30 fL range; and a fixed discriminator
(FD), at 12 fL (used for flagging purposes).
The PLT particle size distribution is used to check the relative height at the LD and UD,
the distribution width, and the existence of two or more peaks.
1 . Mean Platelet Volume (MPV)
MPV is calculated from the following formula.
MPV (fL) =
PCT(%)
PLT (x10
3
/µL)
x 10000
PCT: Weighted frequency of PLT; called the plateletcrit or platelet volume ratio.
2 . PLT Distribution Width (PDW)
PDW is the distribution width at the 20% level when the peak is equivalent to
100%. PDW is expressed in femtoliters (1 femtoliters = 10
-15
liter).
3 . Platelet-Large Cell Ratio (P-LCR)
P-LCR is the ratio of the large platelets found between the FD and UD
discriminators. It is calculated by dividing the number of cells that fall in the range
between the FD and UD, by the number of cells that fall in the range between the
LD and UD.
100%
20%
P-LCR
(LD) (UD)(12fL)
PDW
Figure 10-14: PDW/P-LCR
NOTE:
Customers in the United States:
Platelet Distribution Width (PDW) and
Platelet Large Cell Ratio (P-LCR) parameters have not been
approved for reporting by the Food & Drug Administration (FDA). The
obtained values should be excluded from all print forms until reporting
approval has been obtained. See
Chapter 11: System Setup
for
information on excluding these values.
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