Page 642 - Clinical Hematology_ Theory _ Procedures ( PDFDrive )

626 PART 8 ■ Fundamentals of Hematological Analysis

to aspirate a specimen o anticoagulated whole blood with-

BOX 30.1 out removing the rubber stopper o an evacuated tube. T e

Manual closed mode is essentially the same as the Sampler

mode, but mixing and continuous analysis cannot be per-
VCS Technology ormed automatically. T e Capillary mode is used to analyze

Volume (V): Using direct current impedance, the volume a very small sample o whole blood that has been diluted 1:5.

o each cell is measured. T e XS series o Sysmex instruments are automated

Conductivity (C): Radio requency penetrates the cell, hematology systems consisting o two units: the Main Unit

which generates the data points o cell size and cell that aspirates, dilutes, mixes, and analyzes anticoagulated

internal structure. whole blood specimens and the IPU that processes data

Scatter (S): Midangle scatter detected by a beam o laser rom the Main Unit and provides an operator inter ace. Flags

light that generates data about cellular granularity and and error messages alert laboratory personnel to specimen

cell sur ace structure. abnormalities.

VCS: Single channel that analyzes approximately 8,000 Red cell distribution width, an expression o anisocyto-

cells in a near-native condition. sis, is reported as RDW-SD and RDW-CV. T e RDW-SD is
an actual measurement o the width o the RBC histogram

T e RDW-CV, by comparison, is a mathematically derived

parameter. T e RDW-CV is dependent on the average size

count, correction or WBC inter erence, and the ability to o the RBCs or the MCV. Some models produce nucleated

analyze body f uids, or example, CSF. I the analyzer and RBC and reticulocyte counts. Reticulocytes are enumerated

work cells are combined, many o the preevaluation and by f uorescent f ow cytometry using laser light and a nucleic

postevaluation steps are automated. acid f uorescent dye. Results are reported as RBC-O (opti-

A second Beckman Coulter technology, AccuGate, uses a cal) and reticulocyte number (RE #) and reticulocytes per-

gating method to separate WBCs or RBCS and reticulocytes cent (RE %). Reticulocyte maturation can be assessed. T e

by using contour gates around cell populations. Leukocyte RE -He or reticulocyte hemoglobin equivalent is used to

analysis is per ormed in three dimensions and is displayed monitor the availability o iron in RBCs.

as a 3D cube. Individual cells are represented as points on Hemoglobin is measured using sodium lauryl sul ate

a scatterplot ref ecting cell volume, conductivity, and laser (SLS-hemoglobin method), a noncyanide compound. In the

light scatter characteristics. Reticulocytes is conducted by Sysmex series, erythrocytes and platelets are analyzed by

combining traditional supravital staining with new methy- Hydrodynamic ocusing

lene blue stain and f ow cytometry using VCS technology. ■ Direct current (DC)

NRBC is per ormed using the proprietary VCS technology. ■ Automatic discrimination

A third technology, AccuFlex, allows end users to optimize ■

the levels o individual f ags or improved data point per or- T e leukocyte count is analyzed by the DC detection

mance. Contour discriminators examine areas between di - method and automatic discrimination. A ve-part di er-

erent cell populations. Flagging messages identi y the type ential is produced or leukocytes by a di erential detector

o cell population (e.g., WBC), the suspected variation (e.g., channel (analyzed by RF and DC). A di erential scattergram

variant lymphocytes), and cell date o related condition (e.g., and an immature myeloid in ormation (IMI) scattergram are

abnormal WBC population). A de nitive condition, or produced by f uorescent f ow cytometry. Each cell is mea-

example, leukopenia or leukocytosis, is also generated. sured by orward-scatter laser light, lateral-scatter laser light,

and lateral f uorescent light.
Sysm ex (http://www.sysm ex.com ) T ree additional parameters can be per ormed on the

In the Sysmex X series, there are our modes o sample XE-2100 analyzer. T ese are IG, immature platelet raction

introduction: (IPF), and hematopoietic progenitor cell (HPC).

RBC and WBC cell counts can be per ormed on body f u-
1. Sampler mode ids, including CSF, serous f uid, and synovial f uid.

2. Manual mode

3. Manual closed mode Instrum ent Data Output

4. Capillary mode
Flags or messages are generated i abnormal results are gen-

T e Sampler mode is the primary mode o operation. T is erated. Di erent cell types are distinguished electronically

mode automatically mixes, aspirates, and analyzes samples by impedance by the pulses they generate. T e pulses that

with removing the rubber stopper o an evacuated tube lled are generated are sorted according to size. T ese individual

with anticoagulated blood. In Manual mode, the most com- pulses appear on the oscilloscope and are categorized by

monly used method or S A assay, the rubber stopper o an the computer. From the WBC histogram, the percent and

evacuated tube lled with anticoagulated blood, is manually absolute number o lymphocytes, mononuclear cells, and

removed, and the individual blood sample is aspirated with a granulocytes are determined. Each channel on the x-axis

3
pipette. Using the Manual closed mode, the sampler is used represents size increasing by 1 L (1 L = 1 µm ) rom le