Complete blood count lecture for pediatric residents

1. Rabab Salama
Clinical and Chemical Pathologist
Healthcare Quality Specialist
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Understanding
Complete Blood
Count
(CBC)

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1590 • First microscope
1852-76 • Development of RBC and WBC counting by
hemocytometer by multiple investigators
1878 • Blood cell staining developed by Ehrlich
1929
• Introduction of RBC
indices MCV, MCH,
and MCHC
1940s
• First
automated
analyzer for
counting and
sizing cells by
Coulter

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
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What It Is
The complete blood count
(CBC) is a common blood
test that evaluates the
three major types of cells
in the blood: red blood
cells, white blood cells,
and platelets.

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Why It's Done

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13. Blood Sample:
 Whole Capillary blood or EDTA
anticoagulated venous blood may be
used.
 Minimal volume is 0.5 mL
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14. Blood Sample:
Samples are stable at
room temperature for
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Automated Cell Counters

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Automated Cell Counters

18. Cell Counters
Aperture-
impedance
method
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Light scattering
(optical)
method

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Automated Cell
Counters

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22. DATA OUTPUT U
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NUMERICAL
GRAPHS

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RED BLOOD CELLS ANALYSIS
Red cell Count
More accurate
than manual
method

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Hb concentration
Measured by
cyanmethemoglob
in method using
Drabkin solution.
RED BLOOD CELLS ANALYSIS

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Red Cell
distribution Width
(RDW)
reflects the
variation of red cell
sizes (anisocytosis)
RED BLOOD CELLS ANALYSIS

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RED BLOOD CELLS ANALYSIS

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PLATELETS ANALYSIS

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34. Life Spans of Blood Cells
Blood cell Life span
RBCs 120 days
WBCs
Neutrophils 6 hours to few days
Eosinophils 5 days
Basophils Few hours to few days
Lymphocytes Hours to years
Monocytes Months
Platelets 10 days
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E, B, atypical L, blasts, immature
granulocytes, and plasma cells tended
to fall in the monocyte or granulocyte
region
WHITE BLOOD CELLS ANALYSIS

41. In bacterial infections, neutrophils are most
commonly affected
In viral
infections,
lymphocytes are
most commonly
affected
In parasitic
infections,
eosinophils are
most commonly
affected.
The type of cell affected depends upon its
primary function:

42. In bacterial
infections,
neutrophils are
most commonly
affected
In viral
infections,
lymphocytes
are most
commonly
affected
In parasitic
infections,
eosinophils
are most
commonly
affected

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WHITE BLOOD CELLS ANALYSIS

44. NORMAL WBC PRODUCTION

46. CASE 1

47. CASE 1
CASE 1
A CBC demonstrates normal findings.

48. CASE 1
CASE 1
A normal peripheral blood smear is seen here
with a normal segmented neutrophil and a
lymphocyte.

49. CASE 1
CASE 2
A CBC demonstrates microcytosis and hypochromia.

50. CASE 1
CASE 2
Note the poikilocytosis and microcytosis
and hypochromia in this peripheral blood
smear.

51. CASE 2
CASE 3
A CBC demonstrates megaloblastic changes.

52. CASE 2
CASE 3
A peripheral blood smear demonstrates
megaloblastic changes. Describe the
appearance of the neutrophil.

53. CASE 2
SOURCES OF ERRORS
IN ELECTRONIC
COUNTERS

54. SOURCES OF ERRORS IN
ELECTRONIC COUNTERS
Electrical or
mechanical failures
or even minor
voltage fluctuations
may induce marked
errors in data
collection.
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55. SOURCES OF ERRORS IN ELECTRONIC
COUNTERS
Examples:
 False increase in Hb
level occurs when WBCs
count is very high due to
turbidity.
 Extremely high WBCs
count may falsely raise
the RBCs count and Hct
as the white cell count is
incorporated into the red
cell count.
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56. SOURCES OF ERRORS IN ELECTRONIC
COUNTERS
Examples:
 High glucose levels (>400-600
mg/dl) and the associated
hyperosmolarity cause red cells
swelling and generate a high
MCV, Hct with falsely low MCHC.
 The increased turbidity
associated with hyper lipidaemia
may cause falsely elevated Hb,
MCH, MCHC.
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57. SOURCES OF ERRORS IN ELECTRONIC
COUNTERS
Examples:
 Nucleated red blood cells:
These interfere with the WBC on
some instruments by being counted
as white cells/lymphocytes .
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58. FLAGGING OF AUTOMATED COUNTERS
 It refers to a signal that
the specimen may have
significant abnormality.
 Every instrument has its
flagging system.
 A decision of when a blood
film should be examined
may follow the following
guide

59.  Individual values obtained
from the automated
counters must be
interpreted with clinical
findings.
 Careful examination of the
blood film may add
information that may not be
reflected on average values.
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