Beckman Coulter COULTER LH 750 System, Reference, Page: 50 / 120

PN 4277248DD
3-18
OPERATION PRINCIPLES
PARAMETERS AND THEIR DERIVATION
Reticulocyte (Retic) Parameters
Retic Percent (RET%)
Number of reticulocytes per 100 RBCs. This parameter is directly measured and reported as
%, a percentage of RBCs.The RET% is calculated as the ratio of reticulocytes to the total
number of red cells; this calculation is shown below:
Retic Absolute Number (RET#)
Absolute number of reticulocytes computed from the reticulocyte percent (RET%) multiplied
by the RBC count.
Immature reticulocyte fraction (IRF)
The percentage of the count of the highest light scatter reticulocytes relative to the total count
of the reticulocytes is calculated and is reported optionally as a decimal ratio.
The IRF parameter is an indication of new reticulocyte synthesis. It is calculated from the RET% as
the total number of reticulocyte events in the outermost light scattering region, corresponding to
immature reticulocytes, relative to the total number of reticulocytes and is reported as this ratio.
The algorithm for calculating the IRF parameter is shown below:
Mean reticulocyte volume (MRV)
The average volume of individual reticulocytes derived using VCS reticulocyte algorithm. It is
calculated and is reported in femoliters.
The MRV parameter is the average volume of all reticulocytes (or the mean volume of all retic
events). It is calculated from the RET% and reported in femoliters (fL).
The MRV algorithm is shown below:
Retic%
Retics
∑
Red_Cells
∑
-------------------------------------
x
100 =
RET#
RET% x RBC Count
100
=
IRF
Retics
Region - 3
Region - 10
∑
Retics
Region - 0
Region - 10
∑
------------------------------------------------ =
MRV
Retics_Volume
Region - 0
Region - 10
∑
Retic
Region - 0
Region - 10
∑
------------------------------------------------------------------------ =