COULTER HmX Hematology Analyzer, Справочное руководство

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PN 4237523A 1-4
USE AND FUNCTION
METHOD HISTORY
1.3 METHOD HISTORY
Development
W.H. Coulter (1956) describes the Coulter Principle:
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A suspension of blood cells is passed thru a small orifice simultaneously with an electric
current. The individual blood cells passing thru the orifice introduce an impedance
change in the orifice determined by the size of the cell. The system counts the individual
cells and provides cell size distribution. The number of cells counted per sample is
approximately 100 times greater than the usual microscope count to reduce the
statistical error by a factor of approximately 10 times.
This substantial improvement in precision over previous methods helped to establish the
erythrocyte count as a sensitive index of erythropoietic dyscrasia, particularly when
considered together with Hct and Hgb measurements.
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The COULTER COUNTER
®
Model S analyzer was the first instrument that automated
simultaneous multiparameter measurements on blood. Brittin et al., Gottmann, and Hamilton
and Davidson, reviewed the performance and clinical value of the Model S.
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Refinements of the COULTER COUNTER analyzer to provide accurate size (volume)
distribution data led to a reawakening of interest in pathological erythrocyte size distribution,
first aroused by Price-Jones in 1922.
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Among the advantages offered by the Coulter method of counting and sizing was the ability
to derive an accurate Hct measurement by summing the electronic volume of erythrocytes.
England et al. speculated that electronic Hct measurements did not have the trapped plasma
error of centrifugal Hct measurements.
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Bull et al. described the use of a COULTER COUNTER analyzer for counting thrombocytes.
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This method, useful as it was, depended on preparing thrombocyte-rich plasma to avoid
counting erythrocytes as thrombocytes. Mundschenk et al. and Schulz and Thom discussed
the possibility of counting thrombocytes in the presence of erythrocytes and classifying them
by size.
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Electronic refinements in the Model S-PLUS™ enhanced the accuracy of the
hydrodynamic method. Von Behrens and Paulus also cited the feasibility of counting
thrombocytes by the Coulter method.
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Hemoglobinometry
The lytic reagent used for the complete blood count (CBC) parameters prepares the blood so
the system can count leukocytes and sense the amount of hemoglobin. The lytic reagent
rapidly and simultaneously destroys the erythrocytes and converts a substantial proportion of
the hemoglobin to a stable pigment while it leaves leukocyte nuclei intact. The absorbance of
the pigment is directly proportional to the hemoglobin concentration of the sample.
The accuracy of this method equals that of the hemiglobincyanide method, the reference
method of choice for hemoglobinometry recommended by the International Committee for
Standardization in Hematology (ICSH).
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