Siemens ADVIA 2120, Operator'S Manual, Page: 395 / 477

9-54 Regulatory Information
Reticulocyte Method
Intended Use
The ADVIA 2120/2120i Hematology System Reticulocyte Count (RETIC)
method is intended to quantitatively measure the following reticulocyte
parameters:
•
Reticulocyte concentration (#RETIC)
•
Reticulocyte percentage (%RETIC)
•
Reticulocyte Cell Hemoglobin Content (CHr)
Principles of the Procedure
Reticulocyte Cell Count
Historically, reticulocytes have been assayed by manual methods via the
microscope, in conjunction with nucleic acid stains such as new methylene blue
and brilliant cresyl blue. This method uses a nucleic acid dye (oxazine 750) to
stain cellular RNA.
Two microliters (2 µL) of an EDTA anticoagulated whole-blood sample are
mixed online with the ADVIA 120 autoRETIC reagent. The ADVIA 120
autoRETIC reagent isovolumetrically spheres the erythroid cells and stains
cellular RNA. Low-angle laser light scatter, high-angle laser light scatter, and
absorption characteristics of all cells are counted and measured. The absorption
data are used to classify each cell as a reticulocyte or mature red blood cell based
on its RNA content.
Reticulocyte Size
The method of sizing reticulocytes uses the simultaneous measurement of laser
light scattered at two (2) different angular intervals, which eliminates the adverse
effect of variation in cellular hemoglobin concentration on the determination of
the MCVr parameter.
CHr
The CHr is the mean of cellular hemoglobin content (CH) histogram for the
reticulocyte population.
CHr has been shown to be an early indicator of functional iron deficiency.
Functional iron deficiency has been shown to occur when erythropoietin
(rHuEPO) is employed in the treatment of anemia associated with end stage renal
failure and other diseases. Traditional methods for the detection of iron
deficiency have been shown not to be as sensitive and specific in the detection of
functional iron deficiency.