WBC Count
WBC(leukocyte)
They are cells of the immune system.
• Nucleated
• Big in size
They are 5 types:
• Neutrophils
• Eosinophils
• Basophils
• Lymphocytes
• Monocytes
WBC are separated into a thin white
layer when whole blood is centrifuged
WBC functions
1-Defence and protection against
bacteria, viruses, fungi and parasites.
2-Allergy.
3-Production of immunoglobulins
Normal range:
4-10 X103 cells/µL or cells/mm3
4-10 x109 cells/L
leukocytosis : high number of white
blood cells.
Due to:
chronic infections, inflammation,leukemia
and allergy.
Leukopenia: decreased WBC count
Due to:
chemotherapy, radiation therapy, some
types of cancer ,malaria and TB.
WBC Count
This is a blood test to measure the
total number of white blood cells
(WBCs).
It is almost part of the CBC (complete
blood count).
.
There are several methods that can be
used to determine the number of
leukocytes per microliter of blood :
1- Automatic blood cell counter:
Advantages:
1-The most accurate method
2-the error in results is approximately(1- 2%)
2-Manual WBC count
Advantages:
1-less expensive
2-automated analyzers are not reliable
in counting abnormal cells.
To make the counting of WBC easier
,we use WBC diluent (2% acetic
acid+ gentian violet)
This fluid lyse the red cells and the
WBC remain intact and stain the
nucleus deep violet by the gentian
violet.
Method:
50µL( EDTA blood)+ 0.95 ml of WBC
diluent
The cells are counted on a
hemocytometer
by using the microscope ( 10x 0r 40x)
Count any square from the four large
corner squares indicated by "W". Each
of those squares contains 16 smaller
squares
Light is low
the condenser is down
Dilution
50 µL blood ÷ 50= 1 volume of blood
o.95ml= 950 µLdiluent ÷ 50 = 19 volume
of diluent
1 =1
19+1 20
Dilution =20 times
The volume of 1 corner square is:
1mm (width)X 1mm(height)X 0.1
mm(depth)
= 0.1 mm3 =0.1 µL
Calculation:
N (cells) found in 0.1 µL
size of 1 square
? 1 µl
normal range cells/1 µL
Number of cells in 1ML in diluted blood
=N X 1 = N X 1 =
0.1 1
10
=N X10
WBC in whole blood = Nx10 x20(dilution)
WBC in whole blood =N X 200
disadvantages of manual WBC
count:
1-Require the lyses of erythrocytes
prior to counting white blood cells.
2-This method is less accurate (with
an error of up to 10%)
WBC (leukocytes)
WBCs divided into 2 broad groups
according to function :
1-Phagocyte
2-Immunocyte
Phagocytosis + immune function help in
protect body against infection
Phagocytes:
granulocytes + non granulocyte
e.g:monocyte
immunocytes:
lymphocytes
Granulocytes:
neutrophils
eosinophils
basophils
There are 5 types of mature WBC in peripheral
blood
• NeutrophilL:
mature,band (stab),hypersegmented neutrophil and toxic
granulation
• Basophils
• Eosinophils
• Monocytes
• lymphocytes:
T –lymphocyte, B –lymphocyte and NK(natural killer).
Differences in WBC shapes are in:
• Size of cells
• Nucleus(lobes )
• Granules(size & color)
WBC functions
• Defence and protection against infection
(neutrophils&monocytes)
• Allergy (eosinophils)
• Production of immunoglobulins Ab
(B lymphocytes)
Neutrophil
1- mature neutrophil
• Size: 13M( 3 times bigger than RBC)
• Nucleus: has deep violet nucleus containing 3-5 lobes.
• Cytoplasm: pale cytoplasm with fine pink granules.
• Normal range :40-75%
• Function:
Defense against bacteria.
2-Stab form or band type( young form)
neutrophil
nonsegmented,
long and narrow
nucleus. The band-
like nucleus can
take any shape but
it is never be
straight.
Shift to the left
• increase in the numbers of immature neutrophils,
primarily band forms and metamyelocytes or more
immature cells may also be present; usually in
response to an infection.
3-hypersegmented neutrophil
• Larger than mature neutrophil
• Has more than 5 lobes
• Found in :
• Megaloblastic anaemia
• Chronic infections
• high no of hypersegmented
neutrophil=Shift to the right
4- toxic granulation
• the accumulation
of big, dark
granules in
segmented
neutrophils
• ↑ no of neutrophils (neutrophilia) in case
of:
1- acute bacterial infection
2- acute hemorrhage
3- inflammation
4-tissue necrosis
5-corticosteroid therapy
Eosinophil:
• Cytoplasm: (red orange granules)
Similar to neutrophil except in the cytoplasm, there are
coarse and more deeply red staining granules
• Nucleus: usually have 2 lobes (sunglasses).
• Normal range: 1-6%
• Function:
1-Allergy response
2-Defense against parasite
• Eosinophilia:
1-Allergy
2-Parasitic infection
3-Drug sensitivity
4-Skin disease
Basophils
• in tissue ,they become mast cells.
• only occasionally seen in normal Peripheral blood
• Cytoplasm: have dark blue large cytoplasm granules
which mask the nucleus
• Nucleus: irregular broken nucleus and contain heparin
+ histamin
• Smaller than eosinophils
• Normal range: < 1-2%.
• Basophilia:
1-chronic myeloid leukemia
2-Polycythemia
3-CGL (chronic granulocytic leukemia)
4-Hypothyroidism
5-Ulcerative colitis
6-Nephrosis
7-Delayed hypersensitivity reaction
Monocyte:
• Largest WBC(non granulocyte)
• Multifunction:
• in tissue → phagocytosis
• in immune system →
(1) IFN interferon activation
(2) chemotaxis
(3) phogocytosis
(4) Ag presentation
• Size 15-18 M
• Irregular out lines,
• Cytoplasm: transparent, gray blue cytoplasm giving a
ground glass appearance .
• vaculoes are seen sometimes in the cytoplasm.
• Nucleus: irregular shape usually found as kidney
shape or folded.
• Monocyts spend only short time in marrow and after
circulation for 20-40 hrs leave blood to enter tissues.
• Normal range 2-10%
• Monocytosis:
1-TB
2-Brucellosis
3-Subacute bacterial endocarditis
4-syphilis
5- mainly all types of chronic infection
6-CML (chronic myelomonocytic leukemia)
Lymphocyte:
• Normal range: 20-40%
• Immunocyte
• two unique features characteristic of the immune system:
1-the ability to generate Ag specificity
2 -immunological memory
3 types:
T cells → derived from BM stem cells then pass to thymus to
mature as T-cells ( T helper , T cytotoxic)
B cells → derived from BM stem cells to blood as B-cells
give Abs.
NK → Large cells with cytoplasmic granules,cytotoxic cell
Small lymphocyte
• Small lymphocyte:
• Size 8 M
• Small regular cells
• Nucleus :regular staining with deep dark violet.
• Condensed chromatin and the nucleus is not segmented
filling most of the cytoplasm
• Cytoplasm :stains deep blue
Large lymphocyte
• Large cell about 22 M
• Nucleus: less condensed than small lymphocyte and
more condensed than monocyte and it is round in shape.
• Nucleus color is deep violet.
• Cytoplasm : stained blue and it is abundant and some
times few fine granules are seen
• regular outline.
Small lymphocyte
Large lymphocyte
• Lymphocytosis:
• viral infection
-hepatitis
-CMV( cytomegalovirus)
-infectious mononucleosis
• Lymphoproliferative disorders:
-lymphoma
-CLL ( chronic lymphocytic leukemia)
Absolute values of WBC
• Absolute counts of neutrophil= (70÷100) X 10000= 7000 /
µL
• Neutrophil=2 – 7 X 10 3 / µL
• Lymphocyte=1 -3 X 10 3 / µL
• Eosinophil=0.02-0.5 X 10 3 / µL
• Monocyte=0.2-1 X 10 3 / µL
• Basophil=0.02-0.1 X 10 3 / µL
