quantitation of immature granulocyte forms (the collective
total of promyelocytes, myelocytes, and metamyelocytes).
Ironically, the clinical significance of automated immature
granulocyte counts is difficult to measure at present, since
the existing literature is heavily weighted toward only band
counts and not extended immature granulocyte counts.
We do hope to see these immature granulocyte counts take
hold and, finally, eliminate the use of the manual band
Bayer’s reticulocyte hemoglobin measurement is useful
in the early diagnosis of iron deficiency and in monitoring
Another interesting new channel is hematopoietic
quantitated (for example, in an apheresis product) without
requiring a direct CD34 study on a flow cytometer. This
study is based on differential membrane lipid content.
HPCs have lower membrane lipid content than mature
leukocytes and are preserved after treatment with a lysing
With increasing routine automation of assays that
previously required the use of flow cytometers, we may see
flow cytometers redirected to more in-depth analyses of cell
structure and function—the emerging field of cytomics.
The rate-limiting step on the introduction of new
diagnostic modalities is no longer a matter of how quickly
the technology can be developed, licensed, and deployed.
Far more important is how quickly medical practitioners
embrace the new technologies and incorporate them into
Those selecting hematology instruments can no
longer base their decisions solely on the lowest-price
instrument. Medical considerations should and may
dominate. Perhaps the patient mix requires a parameter
that is available only on certain instruments, for example,
Operational considerations may be paramount—reliable,
high-throughput, easy-to-use instrumentation may be
more crucial than having all the newest parameters on
a more difficult-to-use instrument. The fiscal effect of
eliminating flow cytometry for high-volume studies, such
as CD4 or CD34, may outweigh a higher cost-per-test on
¾ Three-dimensional VCS technology provides the
highest sensitivity, specificity and efficiency in
¾ Compact, bench top analyzer saves valuable laboratory
¾ 75 samples-per-hour throughout maximizes productivity
¾ Detailed reports and histograms for operator review
¾ Automatic calibration and Zero-routine-maintenance
¾ Data management system stores up to 5,000 patient
¾ Closed vial sampling, automatic cap piercing and probe
¾ Walkaway automation frees up valuable operator time
¾ Positive patient ID makes sample tracking easy
¾ Built-in Quality Assurance ensures accuracy.
Coulter MAXM and MAXM AL Hematology
Flow Cytometry Systems (Fig. 9.12)
The MAXM is the easiest hematology system to learn and
operate. It features walkaway operation, positive patient
identification, automatic calibration, auto-probe wipe,
single-operator interface and continuous computer
monitoring of system performance. Best of all, the MAXM
requires no routine daily maintenance. Your staff is free
to handle more complex tasks. The optional Autoloader
allows walkaway operation. Load 25 bar-coded samples
and then just walk away. The MAXM automatically
analyzes both patient samples and controls-providing
automatic printouts of the finished reports at a throughput
of up to 75 samples per hour unsupervised.
Coulter MAXM AL together with Coulter STKS and
the Coulter GEN-STM System offer the only fail-safe
sample management system with positive patient ID and
monitoring of sample integrity both pre and postsampling.
This means peace of mind for you, no reports incorrectly
distributed because of short samples and no mix-up in the
¾ Mean corpuscular hemoglobin concentration
¾ 30 samples per hour for Retics.
¾ 125 μL secondary sample mode
¾ 1,000 sets plus sample analysis screen displays
¾ 5,000 sets plus all sample analysis screen displays for
¾ Near-native state analysis of WBC using four reagents
that are safe to use and discard
¾ Printouts via standard graphics printer with optional
color kit, or single ticket printer.
High Efficiency through Comprehensive Flagging
Instrument-defined suspect abnormalities (User defined
¾ High and low laboratory action limits
DEVELOPMENT OF BLOOD CELLS AND SITES OF
Fetus: Less than 2 months—yolk sac. From 2–7 months:
Liver, with minimal hemopoiesis in spleen.
After 3 months: Hemopoiesis starts in bone marrow.
Full-term infant: Bone marrow is the only site for
production of granulocytes and monocytes. Occurs mainly
in the spleen, lymph nodes and other lymphoid tissues,
though liver and bone marrow produce these in much less
After birth: Same as above except that the monocytes
are provided by the bone marrow, spleen and lymphoid
Extramedullary hemopoiesis (myeloid metaplasia): In
certain disorders the fetal, organs revert to their old
function supported by the reticulum cells, which retain
their potential hemopoietic activity. This occurs when
bone marrow cannot any further fulfil the requirements or
demand imposed upon it, e.g. in:
¾ Growing children with hemolysis
¾ Secondary carcinoma of the bone.
Development of Blood Cells (Flow chart 9.1)
Blood formation has to undergo three stages:
1. Multiplication of precursor cells (1% of all marrow cells
2. Gradual maturation (both structural and functional).
3. Release into the peripheral circulation. The exact
release mechanism is ill understood, granulocytes
achieve this by their motility and RBCs by diapedesis.
Erythroblast is a nucleated red cell.
Normoblast implies normal (reaction) erythropoiesis.
Normoblastic maturation involves:
• Ripening of cytoplasm, i.e. hemoglobinization.
Maturation time from pronormoblast to RBC is 7 days.
Mitotic division occurs till the intermediate normoblast
rim of deep basophilic cytoplasm and has a perinuclear
halo. Nucleus is round and has several nucleoli.
Early normoblast: 10–16 μm, nucleus still large, chromatin
coarser and deeply staining nucleoli disappear.
Intermediate normoblast: 8–14 μm, nucleus smaller,
hemoglobinization commences, cytoplasm takes an
acidophilic tint, chromatin becomes coarser and very
Late normoblast: 8–10 μm, cytoplasm is acidophilic,
nucleus becomes much smaller, later it becomes pyknotic
and is eccentrically placed, ultimately it is lost by extrusion.
Reticulocyte: Flat, non-nucleated, disc shaped, slightly larger
than mature RBC. It shows diffuse pale basophilia, which
appears in the form of a reticulum with supravital stains
(brilliant cresyl blue or new methylene blue). In 1–2 days, it
loses its basophilia and becomes a mature erythrocyte.
Control of erythropoiesis: Erythropoietin (formed in kidneys)
is released in response to lowered tissue oxygen tension.
Erythropoietin is a glycoprotein and stimulates
primitive cell differentiation to pronormoblasts. It
affects the rate of multiplication and maturation. It acts
up to early normoblast stage and also affects the rate of
FLOW CHART 9.1: Development of blood cells
Erythropoietin levels are reduced in:
¾ Transfusion-induced polycythemia.
Erythropoietin levels are increased in:
¾ All anemias except those of renal origin
Specific granules are developed at the myelocyte stage,
which determine the nature of the mature cell.
Development of a Mature Neutrophil
1. Development of specific granules
2. Loss of basophilia of the cytoplasm
3. Nuclear ripening till the segmented stage
4. Ability to be motile and to phagocytose (Mitotic
division occurs till the myelocyte stage only).
Myeloblast: 15–20 μm has a large round or oval nucleus,
evenly stained chromatin in strands or granules with
reticular appearance, 1–6 nucleoli. The cell is peroxidase
Promyelocyte: It is like myeloblast except that it contains
azurophilic granules, which are peroxidase positive.
Nuclear chromatin becomes condenser and nucleoli are
Myelocyte: Specific neutrophilic granules appear, nucleus
shows no nucleoli. N:C ratio reduces, cytoplasm is pale
pink, chromatin thicker and deeply stained.
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