Interpreting the c.b.c & differential blood film Examination C.B.Cs technique & procedure. R.B.Cs WBCs PLATELETS RBCs INDICES: MCV MCH MCHC RDW WBCs Differentials Reticulocytes Band cells Bleeding time clotting time prothrombin time prothrombin concentration INR PERIPHERAL BLOOD FILM: MICROCYTIC ANEMIA MACROCYTIC ANEMIA Target cells aniso-poiklocytes acanthocytes schistocytes

1. (for undergraduates 3rd year Integrated Medicine)
Compiled by Ahmed Redwan, 2021 © copyrighted
Assist. Lecturer Int. Med. Depart.
El-Minia University, EGYPT

3. Introduction:
 Blood is made of two major components;
plasma and cells.
 Plasma is the liquid part of the blood in
which the formed cells are suspended.
 The plasma consists of water, plasma
proteins (a few of which are serum albumin
and globulin and fibrinogen), electrolytes
and other constituents.
 Plasma makes up more than half of the
total blood volume.

4.  The cells are the blood components that will be
discussed in this review. Cells of the blood
include the erythrocytes, which are the red blood
cells/corpusles (RBC); the leukocytes, which are
the WBC; and the thrombocytes, also known as
platelets.
 Blood cells are produced in the bone marrow by
a process called hematopoiesis. Red blood cell
production is regulated by erythropoietin, a
hormone released by the kidneys. When blood
oxygen is low, erythropoietin stimulates the bone
marrow to produce more RBCs.
Introduction (cont.):

5. What Does the CBC Test
Analyze?
The CBC tests for the amount of RBCs,
hemoglobin, hematocrit, reticulocytes, mean
corpuscular volume, mean corpuscular
hemoglobin and mean corpuscular hemoglobin
concentration. Usually, platelets will also be
checked with the CBC.

6. Collection and Panels
 Collection and panel details are as follows:
 Specimen: Whole blood, usually collected
by venipuncture
 Collection: EDTA tube (purple/lavender top;
see image below) containing EDTA
potassium salt additive as an anticoagulant

8. Red blood cells: (RBCs)
Red blood cells: RBCs are the number
of erythrocytes in 1 cubic mm of whole blood.
The RBC count will be low with iron
deficiency, blood loss, hemolysis and bone
marrow suppression.
Increases may be found when one
moves to a higher altitude or after prolonged
physical exercise, and can also reflect the
body’s attempt to compensate for hypoxia.
Normal levels in men and women are 4.6
million-5.9 million and 4.1 million-5.4 million,
respectively.

9. RBCs abnormalities
 Polycythemia vera, a pathologic condition
which is a proliferative disease of the bone
marrow, causes an increase in total RBCs
as well as an elevation in white cells and
platelet count.
 Mild polycythemia may be corrected by
increasing vascular fluid volume, while
more severe cases require frequent
phlebotomies or even radiation or
chemotherapy to suppress bone marrow
production.

10.  Hemoglobin: Hemoglobin is the oxygen-
carrying pigment of red cells. There are
millions of hemoglobin molecules in each red
cell. This blood component carries oxygen
from the lungs to the body tissues.
 Decreases in hemoglobin occur for the same
reasons as decreased RBCs. Normal levels
in men and women are 14-18 g/dl and 12-16
g/dl respectively.

11. Hematocrit: The test for hematocrit measures
the volume of cells as a percentage of the total
volume of cells and plasma in whole blood.
This percentage is usually three times greater
than the hemoglobin.
After hemorrhage or excessive
intravenous fluid infusion, the hematocrit will be
low. If the patient is dehydrated, the hematocrit
will be increased. Normal levels in men and
women are 42 percent-52 percent and 37
percent-47 percent respectively.

12. Reticulocytes “Immature
erythrocytes”
In humans, these are erythroid cells that
have just undergone extrusion of their cell
nucleus.
They still contain some organelles that
gradually decrease in number as the cells
mature. ribosomes are last to disappear.
Certain staining techniques cause
components of the ribosomes to precipitate
into characteristic "reticulum" (not the same
as the endoplasmic reticulum), hence the
name reticulocytes.

14.  Reticulocytes:
complete
arrows.
 RBCs: arrow
heads.
Note the
relatively larger
size of
reticulocytes
(~24%)
And its
polychromatic
nature
(especially clear
with specific
stains).

15.  Reticulocyte: These are the new cells
released by the bone marrow. The reticulocyte
count is therefore used to assess bone
marrow function and can indicate the rate
and production of RBCs.
 Normal to slightly elevated reticulocyte counts
may occur with anemia demonstrating an
underproduction of red cells (such as with iron
or folate deficiencies), depending on the
staging of the disease. Elevated levels may
indicate blood loss or hemolysis. Normal levels
are 0.5 percent to 1.5 percent

20. Indices
 Indices measure the average characteristics
of the erythrocyte.
 The indices usually noted include the mean
corpuscular volume (MCV), mean
corpuscular hemoglobin (MCH), the mean
corpuscular hemoglobin concentration
(MCHC) and red cell distribution width
(RDW).
 MCV: This measures the average size of the
RBC and can be calculated by dividing
hematocrit X10 by RBC count. Normal values
are 80-100 fL.

21.  Low values indicate the cells are microcytic
(small cells) and are often evident with
conditions such as iron deficiency, lead
poisoning and the thalassemias.
 High values greater than 100 fL indicate
macrocytic cells (large cells), and are found
with such conditions as megaloblastic anemia,
folate or Vitamin B12 deficiency, liver disease,
post-splenectomy, chemotherapy or
hypothyroidism.
 The MCV can be normal with a low
hemoglobin if the patient is hypovolemic or
has had an acute blood loss.

22.  MCH: MCH is the average weight of hemoglobin
per red cell. Normal level is 27 to 311 picograms
(pg) or 28-33 pg, depending on the reference.
 MCHC: MCHC is the average concentration of
hemoglobin per erythrocyte. Normal levels can
be seen with acute blood loss, folate and Vitamin
B12 deficiency; these cells will still be
normochromic. Hypochromic or “pale cells” will
be seen with conditions such as iron deficiency
and the thalassemias. Normal levels are 32
percent-36 percent.

23.  RDW: This index is a quantitative
estimate of the uniformity of individual
cell size. Elevated levels may indicate
iron deficiency or other conditions with a
wide distribution of various cell sizes.
Normal levels are 11.5 percent to 14.5
percent.

24. Platelets
 Platelets, also known as thrombocytes, are small elements
formed in the red bone marrow. They are actually
fragments of megakaryocyte cytoplasm (precursor cell to
the platelet.)
 Platelets help to control bleeding. There are two means by
which platelets are able to do this: one is by forming an
occlusion at small injurious openings in blood vessels; and
the second by a thromboplastic function which stimulates
the coagulation cascade. Both platelet number
(measurable by platelet count) and platelet function (not
measurable by platelet count) play a role in the
effectiveness of the platelet in controlling bleeding.
 Note that platelet count measures only platelet number, not
function.

25.  In the cases of thrombocytopenia, the patient will
have decreased platelets and can experience
severe bleeding. Thrombocytopenia may occur for
many reasons, a few of which are:
 aplastic anemia, in which the patient experiences
loss of bone marrow function; drug-induced; or
leukemia, in which the bone marrow is replaced by
malignant cells.
 Certain conditions also reduce platelet function.

26.  Many conditions can elevate platelet number, a few of which
include:
 essential thrombocythemia,
 chronic leukemia (depending on stage and therapy),
 post-splenectomy,
 iron deficiency anemia,
 malignancy, and
 chronic infection or inflammation. The reader should
remember that the staging of the disease process and the
therapeutic regimen can cause platelet number to fluctuate.
 Other conditions may enhance platelet function, a few of
which are atherosclerosis, diabetes, smoking and elevated
lipid and cholesterol levels. These situations can enhance
the patient’s chances of developing thrombosis. The normal
level of platelets is 150,000-350,000/cubic mm.

27. White Blood Cells
 WBCs, also known as leukocytes, are larger in size
and less numerous than red cells. They develop from
stem cells in the bone marrow. WBC function involves
the response to an inflammatory process or injury.
Normal levels of WBCs for men and women are
4,300-10,800/cubic mm.
 When the white count is abnormal, the differential
segment can measure the percentage of the various
types of white cells present. Differential counts add
up to 100 percent. The differential usually includes
neutrophils, bands, eosinophils, monocytes and
lymphocytes.

28.  Though the discussion below lists each differential cell and
describes increases or decreases in percentage in response
to various stimuli, the reader must also remember that most of
these percentages can also fluctuate in patients with certain
kinds of leukemia and other pathologic conditions.
 Neutrophils: The function of neutrophils is to destroy and
ingest bacteria. Neutrophils arrive first at the site of
inflammation; therefore their numbers will increase greatly
immediately after an injury or during the inflammatory process.
 Their life span is approximately 10 hours, then a cycle of
replenishing neutrophils must occur. Besides during
inflammation, neutrophils increase with such conditions as
stress, necrosis from burns and heart attack. Normal levels
range from 45 percent-74 percent.

29. TLC
 Reference ranges for differential white blood
cell counts are as follows [1] :
a) Neutrophils - 2500-8000 per mm3 (55-70%)
b) Lymphocytes - 1400-4000 per mm3 (20–40%)
c) Monocytes - 100-700 per mm3 (2–8%)
d) Eosinophils - 50-500 per mm3 (1–4%)
e) Basophils - 25-100 per mm3 (0.5-1%)

30. Bands: These are occasionally referred to as “stabs” and are
immature neutrophils which are released after injury or
inflammation. The presence of bands indicates that an
inflammatory process is occurring. An increase in the release
of immature cells is known as a “shift to the left.”
In the days of written reports, lab personnel would write
the bands in the left margin, hence the lasting name some
sources claim, which represents an increase of bands or
stabs. However, other references say the shift to the left refers
to the early release of younger white cells such as bands and
metamyelocytes from the bone marrow reserve into the blood
stream (a shift from the right, meaning mature cells, toward
the left of the maturation series, meaning less mature cells).
Normal level ranges from 0 percent-4 percent.

31. o Eosinophils: These are found in such areas as skin and
the airway in addition to the bloodstream. They increase in
number during allergic and inflammatory reactions and
parasite infections. Normal blood levels range from 0
percent-7 percent.
 Basophils: Called basophils when found in the blood,
these cells are also known as “mast” cells when found in
the tissues. Tissue basophils are found in the
gastrointestinal and respiratory tracts and the skin. They
contain heparin and histamine and are believed to be
involved in allergic and stress situations. Basophils may
contribute to preventing clotting in microcirculation. Normal
blood levels range from 0 percent-2 percent.

32.  Monocytes: These cells arrive at the site of injury in
about five hours or more. The monocytes are
phagocytic cells that remove foreign materials such as
injured and dead cells, microorganisms and other
particles from the site of injury, particularly during viral
or bacterial infections. Normal levels, which vary
depending on the source, range from 2 percent-8
percent3 to 4 percent-10 percent.
 Lymphocytes: Lymphocytes fight viral infections; B
cells and T cells are two major types. Lymphocytes
have a key role in the formation of immunoglobulins
(humoral immunity) and also provide cellular immunity.
Normal levels range from 16 percent-45 percent.

33. Immature granulocyte (IG)
 Immature granulocytes (IGs) encompass immature cells of granulocytic
lineages, including metamyelocytes, myelocytes, and promyelocytes,
which are easily recognized morphologically and are reported by
automated analyzer as IG altogether. IG normally absent from
peripheral blood.
 Increased IG occurs accompanied by an increase in neutrophils in the
following conditions:
 Bacterial infections
 Acute inflammatory diseases
 Cancer (particularly with marrow metastasis)
 Tissue necrosis
 Acute transplant rejection
 Surgical and orthopedic trauma
 Myeloproliferative diseases
 Steroid use
 Pregnancy (mainly during the third trimester)

56. Bleeding Time Process
 It involves cutting the underside of the subject's forearm,
in an area where there is no hair or visible veins. The
cut is of a standardized width and depth, and is done
quickly by an automatic device.
 A blood pressure cuff is used above the wound, to
maintain venous pressure at a specified value. The time
it takes for the bleeding to stop (i.e. the time it takes for
a platelet plug to form) is measured. Cessation of
bleeding can be determined by blotting away the blood
every several seconds until the site looks "glassy".

57. BT Interpretation
 Bleeding time is affected by platelet function, certain vascular
disorders and von Willebrand Disease—not by other
coagulation factors such as haemophilia. Diseases that cause
prolonged bleeding time include thrombocytopenia,
disseminated intravascular coagulation (DIC), Bernard-Soulier
disease, and Glanzmann's thrombasthenia.
 Aspirin and other cyclooxygenase inhibitors can significantly
prolong bleeding time. While warfarin and heparin have their
major effects on coagulation factors, an increased bleeding
time is sometimes seen with use of these medications as well.
 People with von Willebrand disease usually experience
increased bleeding time, as von Willebrand factor is a platelet
adhesion protein, but this is not considered an effective
diagnostic test for this condition.
 It is also prolonged in hypofibrinogenemia.

58. Clotting time
 Clotting time is the time required for a sample of
blood to coagulate in vitro under standard
conditions.
 There are various methods for determining the
clotting time, the most common being the capillary
tube method. It is affected by calcium ion levels
and many diseases. Normal value of clotting time
is 2-8 minutes.
 For the measurement of clotting time by test tube
method, blood is placed in a glass test tube and
kept at 37° C. The required time is measured for
the blood to clot.

59.  There are several other methods, including testing
for those on anticoagulants, such as heparin or
warfarin.
 Activated partial thromboplastin time (aPTT) is used
for heparin studies and the normal range is 20–36
seconds, depending upon which type of activator is
used in the study.
 Prothrombin time (PT) is used for warfarin studies.
PT time for adult males' normal range is 9.6–11.8
seconds, while adult females' normal range is 9.5–
11.3 seconds.
 Internationalized normalized ratio (INR) is also a
warfarin study, with target ranges of 2–3 for standard
warfarin and 3–4.5 for high-dose warfarin.

60.  The international normalized ratio (INR)
recommendations below are per guidelines
from the American College of Chest
Physicians in Cerebrovascular event INR
target (range):
 Atrial fibrillation (AF) plus ischemic stroke
or transient ischemic attack (TIA): 2.5 (2.0-
3.0) [2, 3, 4, 5, 6]
 Venous sinus thrombosis: 2.5 (2.0-3.0)
 Duration of therapy: Long-term
 AF plus ischemic stroke or TIA: Long-term
 Venous sinus thrombosis: 12 months

62. Thank You
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