SYSMEX KX-21 - Page 238

FUNCTIONAL DESCRIPTION
Sysmex KX-21 Operator’s Manual -- Revised October 1998 9-21
2. PLT Histogram
Platelet histogram is analyzed using three discriminators: two discriminators (LD) and
(UD) - determined automatically between 2 - 6 fL and between 12 - 30 fL, respectively
-and the fixed discriminator at 12 fL. Regarding PLT histogram, check is made to see
that there are no relative frequency errors at discriminators (LD) and (UD), distribution
width error, and there is a single peak.
1) PDW (PLT Distribution Width)
PDW is the distribution width on 20% frequency level with the peak taken as
100%. The unit applied is fL (femto = 10
-15
L).
• Definitions of PDW and P-LCR
100%
20%
P-LCR
(LD)
(UD)
(12fL)
PDW
Figure 9-6-15: Definitions of PDW and P-LCR
2) MPV (Mean Platelet Volume)
MPV is calculated by the following formula:
MPV (fL) =
PCT (%)
PLT (×10
3
/µL)
×1000
Where PCT (%) represents the value weighted with PLT frequency and is called
platelet-crit or platelet volume ratio. The analysis method used is the same as
mentioned in HCT analysis principle 4.2 RBC/PLT Analysis Flow in this chapter.
3) P-LCR (Large Platelet Ratio)
This is the ratio of large platelets exceeding 12 fL discriminator and is calculated
as the ratio of the particle count between the 12-fL fixed discriminator and Upper
discriminator (UD) to the particle count between Lower discriminator (LD) and
Upper discriminator (UD).