• Automated cell counters are widely called Coulter

OVERVIEW OF CLINICAL HEMATOLOGY counters.

• The average human possesses 5L of blood. • The Coulter principle of direct current electrical
impendance is still used in automated cell
• Blood transports oxygen from lungs to tissues; counters to count RBCs
clears tissues of carbon dioxide; transports
glucose, proteins, and lipids; and moves waste to
theliver and kidneys. Morphology - Cell appearance it encompasses cell color,
• The liquid portion of the blood is the plasma - size, shape, cytoplasmic inclusions ad nuclear
provides coagulation enzymes that protect vessels condensation.
from trauma and maintain circulation
• Plasma trasnports and nourishes blood cells.
• Hematology is the study of the blood cells RED BLOOD CELLS
• By staining counting analyzing and recording the • Anucleate, biconcave, discoid cells.
appearance, phenotype and genotype of all three • Filled with a reddish protein called hemoglobin
types of cells, the medical laboratory professional w/c transports oxygen and carbon dioxide.
is able to predict, detect and diagnose blood • Appears salmon pink and measures 7-8
diseases and many systemic diseases that affect micrometer in diameter w/ a zone of pallor that
blood cells. occupies one third of their center.
• Physicians rely on hematology laboratory test • RBCs in the earlier times were counted to detect
results to seect and monitor therapy for these anemia or polycythemia.
disorders; consequently, a complete blood count • Anemia - loss of oxygen carrying capacity and is
(CBC) is ordered on nearly everyone who visits a often reflected in a reduced RBC count or
physician or is admitted to a hospital. decreased RBC hemoglobin concentration.

HISTORY When this happens, the erythrocyte loses its

capacity to carry oxygen.
Athanasius Kircher in 1657 - described 'worms' in the The RBCs also have a larger zone of pallor when
blood. 1st person who viewed infected blood samples suffering from anemia.
under the microscope. The patients were suffering from • Polycythemia - increased RBC count reflecting
the Italian Plague. increased circulating RBC mass that leads to
hyperviscosity.
Anton van Leeuwenhoek in 1674 gave an account of
RBCs DIAGNOSTIC ASSAYS
Giulio Bizzozero - described platelets as "petites
plaques" RBC Count (Manual)
• We use whole blood + 0.85% normal saline
James Homer Wright - developed the Wright stain solution
which opened a new world of visual blood film • Uses a special pipette known as the Thoma
examination through the microscope. pipette to aspirate whole blood and mix in
• Wright's Romanowsky--type stain (polychromatic, order for us to achieve the dilution of 1:200
a mixture of acidic and basic dyes) and which is the proper dilution for the RBC count.
refinements remains the foundation of blood cell • Diluted blood is transferred to a
identification. Hemacytometer. It is an instrument where we
In the present-day hematology laboratory, RBC WBC drop a portion of the sample then cover it with
and platelet is analyzed though automation or visually a cover slip and view it under a microscope.
using 500x to1000x light microscopy examination of *Nowadays, this method is rarely used for we now
cells fixed to a glass microscope slide and stained with a process RBC count through a Coulter Counter.
Wright or Wright-Giemsa stain.

Joseph and Wallace Coulter - patented the first

electronic counter in 1953.
Hemoglobin Measurement Anisocytosis – extreme RBC volume variability on the
Wright-stained blood film as variation in diameter.
• Hemoglobin measurement relies on a weak
solution of potassium cyanide and potassium RBC indices provides stable measurements for internal
ferricyande called Drabkin reagent. quality control of automated blood cell analyzers.
- In this process the aliquot of whole blood is
mixed with a measured volume of the Drabkin
reagent . RETICULOCYTES
• Immature RBC/ young erythrocytes.
*After it was discovered that these substances are • Newly released from the bone marrow
toxic they were replaced with Sodium lauryl • Stained with nucleic acid stains or vital
sulfate. stains/supravital stains.
WHITE BLOOD CELLS
• Through the Drabkin reagent The
hemoglobin here is converted into a stable • Also known as leukocytes.
cyamethemoglobin or hemeglobincyanide, • Are a loosely category of cell types dedicated to
and the absorbance of the solution is protecting their host from infection and injury.
measured in a spectrophotometer at 540 • WBC are transported in the blood from either
nm wavelength. the bone marrow or lymphoid tissue to the
tissue or body cavity destination.
• Hematocrit is the ratio of volume of packed RBCs • They are called WBCs for they are nearly
to the volume of whole blood and is manually colorless in an unstained cell suspension.
determined by transferring blood to a plastic tube • Are counted visually though a microscope and a
with a unform bore, centrifuging, measuring the hemacytomer.
column of RBCs and diving by the total length of • The technique to count WBCs is the same as
the column of RBCs plus plasma. RBCs but the typical dilution is 1:20 and the
• Hematocrit is also known as packed cell volume dilutent is a dilute acid solution.
(PCV), the packed cells referring to the RBCs.
• The acid causes RBCs to lyse. If there is no acid
• Buffy Coat - is the light colored layer between the
used, the RBCs which are numerous shall
RBCs and plasma. It contains the WBCs and
obscure the WBCs.
platelets which are excluded in the hematocrit
• Like the RBC count, the WBC count has been
determination.
replaced by automated blood cell analyzers.
• The analyzing of body fluids such as CSF or
The medical laboratory professionals may use the three
pleural fluid may employ visual RBC counting.
numerical results which are the RBC count, HGB and
HCT to compute the RBC indices such as:
Leukopenia – the decreased WBC count.
• Mean cell volume (MCV) – Reflects RBC
Leukocytosis – Increased WBC count
diameter w/c is the size of the RBC. Repoted in
femtoliter (fL)
Types of WBC
• Mean cell hemoglobin (MCH) – mass
hemoglobin per cell. It checks the measure of
WBCs are subdivided into two groups namely
hemoglobin content. Repoted in picograms (pg)
granulocytes and agranulocytes.
• Mean cell hemoglobin concentration (MCHC) –
refers to the RBC staining intensity & amount of Granulocytes – has prominent cytoplasmic granules.
central pallor. Reported in grams per decilitre They are as follows:
(g/dL)
• Neutrophil – phagocytic cells whosemajor
*There is a 4th indices that is measured
purpose is to engulf and destroy
RBC distribution width (RDW) – expresses the degree if
microorganisms and foreign material and either
variation in RBC volume.
directly or after they have been labled for
RDW is based on the standard deviation of RBC volume
destruction by the immune system.
and is routinely reported by automated.
Segmented- refers to their multilobed nuclei. The count and is often associated with drug therapy
cytoplasm of neutrophil contains pink- or lavender- or immunodeficiency.
staining granules filled with bactericidal substances.

Neutrophilia – increase in neutrophils. This often signals

• Monocytes – is an immature macrophage
bacterial infection.
passing through the blood from its point of
origin, usually the bone marrow, to a targeted
Neutropenia – a decrease in neutrophil and is often
tissue location.
caused by certain medications and viral infections.
Macrophages are the most abundant cell type in the
• Bands – a slightly less mature neutrophil with
body although monocytes comprise a minor component
non segmented nucleus in a U or S shape.
of peripheral blood WBCs.
Left shift – an increase in Bands which also signals
They occupy every body cavity; some are motile and
bacterial infection.
some are immobilized. Their tasks are to identify and
phagocytize (engulf and consume)
• Eosinophils – Cells that have a round, bright
foreign particles and assist the lymphocytes in mounting
orange-red cytoplasmic granules filled with
an
proteins involved in immune system regulation.
immune response through the assembly and
presentation ofantigen epitopes.
Eosinophilia – elevated eosinophil count. This often
signals a response to allergy or parasitic infection.
Monocytes, when observed on a microscope have:
• Basophil – cells with dark purple, irregular
• blue-gray cytoplasm with fine azure granules
cytoplasmic granules that obscure the nucleus.
• a nucleus that is usually indented or folded.
The granules contains histamines and various
other proteins.
Leukemia – an uncontrolled proliferation of a clone of
malignant WBCs.
Basophilia- elevated basophil count. That often signals
• It may be chronic
a hematologic disease. Basophilia is rarely occurs in the
• may involve any of the cell lines and are
body.
categorized by their respective
immunophenotypes and genetic aberrations.
Agranulocytes – WBCs that do not have prominent
cytoplasmic granules. They are:
PLATELETS
• Lymphocytes – comprises of a complex system
• Also known as thrombocytes
of cells that provide for host immunity
• True blood cells that maintains blood vessel
-They recognize foreign antigens and mount integrity by initiating wall repairs.
humoral (antibodies) and cell-mediated • They adhere to surfaces of damaged blood
antagonistic responses. vessels
• Forms aggregates with naighboring platelets to
On a Wright-stained blood film, most plug the vessels.
lymphocytes are nearly round, are slightly larger • Secrete proteins and small molecules that
than RBCs, and have round featureless nuclei trigger thrombosis or clot formation.
and a thin rim of nongranular cytoplasm. • They are major cells that control hemostasis -
series of cellular and plasma-based mechanisms
Lymphocytosis – an increase in the lymphocyte that seal wounds, repair vessel walls, and
count and often associated with viral infections. maintain vascular
patency (unimpeded blood flow)
Lymphocytopenia – also known as lymphopenia
pertains to the abnormally low lymphocyte • Platelets are only 2-4 micrometer in diameter
and slightly granular
 • The technique used in counting platelets is the • The coagulation system employs a complex
same as that of counting WBCs on a sequence of plasma proteins, some enzymes,
hemacytometer. Though a different counting and some enzyme cofactors to produce clot
area, dilutent and dilution id used. formation after blood vessel injury. Another six
• Since platelets are hard to distinguish in a to eight enzymes exert control over the
hemacytometer automated blood cell analyzers coagulation mechanism, and a third system of
have largely replaced visual platelet counting enzymes and cofactors digests clots to restore
and provide greater accuracy vessel patency, a process called fibrinolysis.

Tests done for coagulation are:

COMPLETE BLOOD COUNT • prothrombin time
• partial thromboplastin time(or activated partial
• It is performed on automated blood cell thromboplastin time),
analyzer and • thrombin time (or
• In collecting the integrity of the blood specimen • thrombin clotting time),
must be ensured such as putting it in the • fibrinogen assay, and
appropriate anticoagulant and tube. • D-dimer assay
• The specimen should be free from clot and
hemolysis.
• The specimen should also be of sufficient
volume for “short draws” results in incorrect
anticoagulant-to-blood ratio.

Accession – specimen accession is a process

where the specimen must be accurately
registered in the work list. It can be
automated, relying on bar codes or radio
frequency identification (RFID) tech which
reduces the instances of identification error.

Flag – an indication when one of the results from a

blood cell analyzer is abnormal. When this happens a
blood film examination is performed.

BLOOD FILM EXAMINATION

• It is a specialized, demanding, and fundamental

CBC activity.
• Prepare a “wedge-prep” blood stained using
Wright or Wright-Giemsa stain.
• There are two types:
➢ Thin Smear
➢ Thick Smear
COAGULATION
• It involves the platelets.
• Platelets are a key component of hemostasis, as
previously described; plasma coagulation is the
second component.
• In a surgical operation, coagulation tests are
done to determine has the ability to promote
clotting.