don't overlook the CBC!

1. INTERPRETATION OF
COMPLETE BLOOD
COUNT
A SIMPLE TEST, A GREAT
VALUE
By : Alaa M Abozied

2. Introduction :
 The complete blood count (CBC) is one of the
most commonly ordered blood tests. The
complete blood count is the calculation of the
cellular (formed elements) of blood. These
calculations are generally determined by special
machines that analyze the different components
of blood in less than a minute.
 A major portion of the complete blood count is
the measure of the concentration of white blood
cells, red blood cells, and platelets in the blood

3. The complete blood count, or CBC, lists a number of
many important values. Typically, it includes the
following:
 White blood cell count.
 WBC differential count
 Red blood cell count .
 Hematocrit(Hct)
 Hemoglobin (Hbg)
 Mean corpuscular volume (MCV)
 Mean corpuscular hemoglobin (MCH)
 Red cell distribution width (RDW)
 Reticulocytic count
 Platelet count
 Mean Platelet Volume (MPV)

4. Interpretation ?
 Reports layouts vary, so you need to
understand what's behind the numbers.
 Always ask yourself, do the results fit with the
clinical situation ?

5. Let’s start with normal CBC:
let’s start with WBCs:
 White blood cell count (WBC) is the number
of white blood cells in a volume of blood.
Normal range varies slightly but is generally
between 4,300 and 10,800 cells per cubic
millimeter (cmm). This can also be referred to
as the leukocyte count and can be expressed in
international units as 4.3 to 10.8 x 109 cells per
liter.

6. White blood cell (WBC), differential
count.
 White blood count is comprised of several
different types that are differentiated, or
distinguished, based on their size and shape.
The cells in a differential count are
granulocytes, lymphocytes, monocytes,
eosinophils, and basophils.
 Neutrophils: 50 - 70%
 Lymphocytes: 20 - 40%
 Monocytes : 1 - 6%
 Eosinophils : 1 - 5%

8. 8For Financial Professional Use Only
Absolute Neutrophil Count
TEST RESULT UNITS REF RANGE
WBC 5.2 x 1000/mm3 3.9 - 11.1
RBC 3.81 L x 106/mm3 4.20 - 5.70
HGB 14.5 g/dL 13.2 - 16.9
HCT 41.2 % 38.5 - 49.0
MCV 98 H fl 80 - 97
MCH 33.7 H pg 27.5 - 33.5
MCHC 35.3 % 32.0 - 36.0
RDW 11.8 % 11.0 - 15.0
PLT 172 x 1000/mm3 140 - 390
MPV 7.6 fl 7.5 - 11.5
NEUT % 40.1 % 38.0 - 80.0
LYMPH % 46.1 % 15.0 - 49.0
MONO % 12.9 % 0.0 - 13.0
EOS % 0.6 % 0.0 - 8.0
BASO % 0.3 % 0.0 - 2.0
NEUT, ABS 2085 cells/mm3 1650 - 8000
LYMPH, ABS 2397 cells/mm3 1000 - 3500
MONO, ABS 671 cells/mm3 40 - 900
EOS, ABS 31 cells/mm3 30 - 600
BASO, ABS 16 cells/mm3 0 - 125
5.2 x 1000 = 5200
5200 x .401 = 2085

9. Red Blood Cells (RBCs)
 Largest cellular component of blood, about 40-
45% of blood volume
 Red blood cells normally last about 120 days
before they are removed by the spleen.
 Normal range varies slightly between
laboratories but is generally from 4.2 to 5.9
million cells/cmm

10.  Hemoglobin (Hb). This is the amount of
hemoglobin in a volume of blood.. Normal
range for hemoglobin is different between the
sexes and is approximately 13 to 18 grams per
deciliter for men and 12 to 16 for women.

11. RBC indices
 Hematocrit: (packed cell volume) is the
volume percentage (%) of red blood cells
in blood. It is normally about 45% for men and
40% for women
 Mean corpuscular volume (MCV)
Is the average volume of a red blood
cell. This is a calculated value
derived from HCT/RBC count .
Normal range may fall between
80 to 98femtoliters

12. RBC indices ; continue
 MCH (mean corpuscular hemoglobin) is the average
amount of hemoglobin in the average red cell.
HB/RBCs = 27-32 pg/cell
 MCHC (mean corpuscular hemoglobin
concentration) is the average concentration of
hemoglobin in a given volume of packed
RBC.
HB/HCT= 26-34%
 RDW (red cell distribution width)
is a measurement of the variability of red cell size
and shape. Higher numbers indicate greater
variation in size. Normal range is 11 to 15

13. The Reticulocyte Count
• Reticulocytes are immature red blood cells,
typically composing about 1-2 % of the red
cells in the human body. Reticulocytes develop
and mature in the bone marrow and then
circulate for about a day in the blood stream
before developing into mature red blood cells.

14. Platelet count.
 Platelets are not complete cells, but actually
fragments of cytoplasm (part of a cell without
its nucleus or the body of a cell) from a cell
found in the bone marrow called a
megakaryocyte. Platelets play a vital role in
blood clotting. Normal range varies slightly but
is in the range of 150,000 to 400,000/ cmm
(150 to 400 x 109/liter). Life span 7-10 days

15. Mean Platelet Volume (MPV)
 The average size of platelets in a volume of
blood.
 Normal range is given as 7.5-11.5 fL.

16. Abnormal
CBCs
interpretation

17. The Good, The Bad, and The Ugly
Common Abnormal but Benign
CBCs
(CBC may be accepted without repeat
CBC or clinical evaluation)
• Mild iron deficiency anemia in pre-menopausal women
• Beta thalassemia minor
• Chronic benign neutropenia
• Reactive thrombocytosis
Abnormal / Worrisome CBCs
(may require additional follow-up
or clinical evaluation)
• Iron deficiency anemia in men or post-menopausal women
• Mild or moderate anemia, not fully evaluated
• Unexplained thrombocytopenia or thrombocytosis
• Mild abnormalities involving all 3 cell lines (red cells, white cells,
and platelets), mild pancytopenia
Markedly Abnormal CBCs • Leukemia
• Severe anemia
• Severe leukopenia or severe pancytopenia

18. Simply abnormalities in CBCs are
“Too high” or “Too low” counts and
next step is to find causes of this
abnormal results in clinical context ,
and what are further investigations
you will order to confirm the
diagnosis?

19. Leukocytosis
 Elevated total WBCs more than 10,800 cells per
cubic millimeter (cmm), this can result from many
causes, principally infections and inflammatory
disorders.
 Cancer and myeloproliferative disorders can also
cause high, sometimes extremely high, WBC
counts
 Elevated one of the differential WBCs count is
more specific and useful to interpret.
There are five principal types of leukocytosis:
 Neutrophilia (the most common form)
 Lymphocytosis Monocytosis

20. Leukemoid reaction ; cont.
Causes of leukemoid reaction:
1. Hemorrhage
2. Drugs use as sulfa drugs, Dapson ,
glucocorticoids
3. and G-CSF or related growth factors
4. Infections as Clostridium difficile ,Tuberculosis ,
Pertussis and infectious mononucleosis
(lymphocyte predominant)
5. splenectomy
6. Diabetic ketoacidosis
7. Organ necrosis as hepatic necrosis or ischemic
colitis

21. Leukemoid reaction
 The term leukemoid reaction describes an
elevated white blood cell count, or leukocytosis,
that is a physiological response to stress or
infection (as opposed to a primary blood
malignancy, such as leukemia).
 It may be lymphoid or myeloid.
 Conventionally, a leukocytosis exceeding
50,000 WBC/mm3 with a significant increase in
early neutrophil precursors is referred to as a
leukemoid reaction.

22. Leukemoid reaction ; cont.
 The peripheral blood smear may show
myelocytes, metamyelocytes, promyelocytes,
and rarely myeloblasts; however, there is a mix
of early mature neutrophil precursors, in
contrast to the immature forms typically seen
in acute leukemia.
 Serum leukocyte alkaline phosphatase (LAP
score) is normal or elevated in leukemoid
reaction, but is depressed in chronic myeloid
leukemia. However, at present the test of
choice in adults to distinguish CML is an assay
for the presence of the Philadelphia
chromosome.

23. Neutrophilic leukocytosis (neutrophilia)
 Elevated absolute neutrophilic count above
8.000 cells/mm cubic
 Acute bacterial infections, especially pyogenic
infections.
 Inflammation.
 Tissue necrosis.
 Myocardial infarction.
 Burns.
 Rarely leukemia as CNL.

24. Shift to the left & shift to the right ?
 Left shift or blood shift is an increase in
the number of immature leukocytes in
the peripheral blood, particularly
neutrophil band cells. Main cause is
bacterial infections.

25.  Right shift is less commonly used term and
means more maturation of neutrophils
appear in blood film as hyperlobulated
neutrophils and reduced count or lack of
"young neutrophils" (metamyelocytes, and
band neutrophils) in blood smear.
 This fact shows suppression of bone marrow
activity, as a hematological sign specific for
pernicious anemia.

26. Lymphocytosis
 In adults, absolute lymphocytosis is present when
the absolute lymphocyte count is greater than 4000
per microliter, in older children greater than 7000
per microliter and in infants greater than 9000 per
microliter.
 Lymphocytes normally represent 20 to 40% of
circulating white blood cells. Relative
lymphocytosis occurs when there is a higher
proportion (greater than 40%) of lymphocytes
among the white blood cells, while the absolute
lymphocyte count (ALC) is normal (less than 4000
per microliter). Relative lymphocytosis is normal in

27. Lymphocytosis; cont.
 Causes :
 Chronic infections as Tuberculosis and Brucellosis
 Viral infections
Hepatitis
Cytomegalovirus infection
Infectious mononucleosis
Pertussis
 some forms of malignancy,
such as lymphocytic
leukæmias

28. Eosinophilic leukocytosis (eosinophilia)
 Elevated absolute eosinophilic count above
0.45×109/L (450/μl).
Causes :
 Allergic disorders as asthma , Hay fever and drug
allergies.
 Allergic skin diseasesas Pemphigus and dermatitis
herpetiformis
 Parasitic infections.
 Neoplastic eosinophilia as some forms of malignancy ;
Hodgkin's lymphoma, NHL and chronic eosinophilic
leukemia.
 Systemic autoimmune diseases (e.g. SLE)
 Some forms of vasculitis

29. Eosinophilia ; cont.
 The hypereosinophilic syndrome (HES) is a
disease characterized by a persistently
elevated eosinophil count (≥ 1500/mm³) in the
blood for at least six months without any
recognizable cause, with involvement of either
the heart, nervous system, or bone marrow.
 HES is a diagnosis of exclusion, after clonal
eosinophilia (such as leukemia) and reactive
eosinophilia have been ruled out.

30. Monocytosis
Causes
 Chronic infections as Tuberculosis
, bacterial endocarditis and Malaria
 Systemic autoimmune diseases, e.g. SLE
 Inflammatory bowel diseases, e.g. ulcerative
colitis
 Neoplastic monocytosis as chronic
myelomonocytic leukemia (CMML).

31. Basophilic leukocytosis(Basophilia)
 Basophilia as an isolated finding is uncommon.
However it is a common feature of
myeloproliferative disorders and particularly
prominent in chronic myelogenous leukemia.

32. Leucopenia
 Decrease in the number of white blood cells
below 4,300 per cubic millimeter.
 The terms leukopenia and neutropenia may
occasionally be used interchangeably, as the
neutrophil count is the most important indicator
of infection risk
 Neutropenia detected when absolute
neutrophilic count is less than 1500 cells per
cubic milliliter.

33. Neutropenia
 There are three general guidelines used to
classify the severity of neutropenia based on the
absolute neutrophil count (ANC) (expressed
below in cells/µL)
 Mild neutropenia (1000 ≤ ANC < 1500) : minimal
or significant increase in risk of infection.
 Moderate neutropenia(500 ≤ ANC < 1000):
moderate risk of infection, fever can be treated as
outpatient.
 Severe neutropenia (ANC < 500) : severe risk of
infection.Treat fever with IV antibiotics as
inpatient.

34. Neutropenia ; causes
Decreased production in the bone marrow due
to:
 Aplastic anemia
 cancer, particularly blood cancers
 hereditary disorders (e.g. congenital neutropenia,
cyclic neutropenia)
 Radiation
 Vitamin B12, folate deficiency.
Increased destruction:
 Autoimmune neutropenia.
 chemotherapy treatments, such as for cancer and
autoimmune diseases

35. Medications :
 Phenytoin , indomethacin, propylthiouracil ,
carbimazole
, trimethoprim/sulfamethoxazole antipsychotic
drugs and interferon therapy.
 There is often a mild neutropenia in viral
infection.
 Chronic idiopathic neutropenia is adiagnosis of
exclusion . It may be severe but usually has
benign course.

36.  CYCLIC NEUTROPENIA:
 a form of neutropenia that tends to occur
every three weeks and lasting three to six days
at a time due to changing rates of cell
production by the bone marrow. It is often
present among several members of the same
family. Treatment includes G-CSF and usually
improves after puberty.

37. Anaemia:
 Anemia is the most common disorder of the
blood. Diagnosis made when haemoglobin
level is lower than 13g/dl in males and 11.5
g/dl in females.
 It can be classified in a variety of ways, based
on the morphology of RBCs or underlying
etiologic mechanisms.
 When we interpret a CBC report showing
anaemia by low haemoglobin level , we
should look for RBC indices reticulocytic count
and blood film to detect which type of
anaemia.

38. Anaemia according MCV
Microcytic
MCV
Normocytic Macrocytic
Iron Deficiency IDA
Chronic Infections
Thalassemias
Hemoglobinopathies
Sideroblastic
Anemia
Chronic disease
Early IDA
Hemoglobinopathies
Primary marrow disorders
Combined deficiencies
Increased destruction
Megaloblastic anemias
Liver disease/alcohol
Hemoglobinopathies
Metabolic disorders
Marrow disorders
Increased destruction

39. MCHC ?
RDW ?
Reticulocytes ?

40. Causes of reticulocytosis
 Acute Blood loss or Hemorrhage
 Acute Hemolysis or Hemolytic Anemia
 Microangiopathic Anemia
 Post-splenectomy
 Hemoglobinopathy

41. Reticulocyte percentage index:
 It is a calculated value used in the diagnosis of
anemia. This calculation is necessary because
the raw reticulocyte count is misleading in
anemic patients.

42.  The reticulocyte index (RI) should be between
1.0% and 2.0% for a healthy individual.
 RI less than 2% with anemia indicates loss of
red blood cells, but decreased production of
reticulocytes (ie, an inadequate response to
correct the anemia) and therefore red blood
cells.
 RI > 3% with anemia indicates loss of red
blood cells (from causes such as destruction,
bleeding, etc.), with an increased
compensatory production of reticulocytes to
replace the lost red blood cells.

43. Elevated hemoglobin:
 When hemoglobin level is above 18.5 g/dl in
males and 16.5 g/dl in females it is called
erythrocytosis or polycythemia
 Also HCT is raised above 51 and 48 in male
and females respectively.
 We should differntiate between
pseudopolycythemia and true polycythemia.
 True polycythemia means increase of total red
cell mass.

44.  COPD
 Dehydration
 Emphysema
 Heart failure
 Kidney malignancy
 Living at a high altitude, where there's less oxygen in
the air
 Other types of heart disease
 Other types of lung disease
 Polycythemia vera
 Smoking, which may result in low blood oxygen levels

45. Platelet count abnormalities
 Decreased platelet count below 150,000 /
cmm is called thrombocytopenia and high
counts above 40.000 / cmm is called
thrombocytosis.

46. 46
Platelet count abnormalities
Possible Causes of
Thrombocytosis:
Possible Causes of
Thrombocytopenia:
Common: “Reactive” thrombocytosis
related to acute trauma, surgery,
blood loss, iron deficiency, chronic
infections (osteomyelitis),
inflammatory diseases including
rheumatoid arthritis and ulcerative
colitis, splenectomy
Uncommon: polycythemia vera,
essential thrombocytosis , some
cancers
Common: spurious lab result
caused by platelet clumping,
idiopathic or immune-mediated
thrombocytopenia (ITP),
medications, viral infection
Uncommon: hemolytic-uremic
syndrome, leukemia, sepsis,
hypersplenism

47. Mean platelet volume:
 Young” platelets, recently released from the
bone marrow, are typically slightly larger
 Often elevated in immune or idiopathic
thrombocytopenic purpura (ITP)
In an individual with low platelet count
(thrombocytopenia):
 Increased MPV indicates normal bone marrow
response.
 Decreased or low normal MPV may indicate
impaired bone marrow response.

48. Another 3 questitions :
Normoblastemia
Corrected WBC count
Leucoerythroblastic reaction

49.  Normoblast is a type of red blood cell which
still retains a cell nucleus. It is the immediate
precursor of a normal erythrocyte.
 It mainly present in hypercelluar bone marrow
conditions as hemolytic anemias.

50.  The WBC by any method is a count of nuclei or total
nucleated cell count. If nucleated red blood cells
(nRBC) are circulating in blood, they will be included
in the nucleated cell count whether the count is
done by manual methods or by automated
analyzers.
 In such cases, the WBC represents the leukocyte count only
after it has been corrected for the nucleated red cells
(nRBCs). The number of nRBCs per 100 leukocytes is
recorded during the differential leukocyte count. Then a
correction is made as follows:
WBC Count x 100
____________________
NRBC's observed + 100

51. Leukoerthyroblastic reaction
 Leukoerthyroblastic change refers to the
presence of nucleated red blood cells and
primitive white blood cells in peripheral blood.
 It can be the bone marrow response to any
irritation including marrow infiltration [causing
immature red cells]. Marrow infiltrative
disorders include myelomas, malignancy,
myelofibrosis, Gaucher’s disease etc. It can
also occur as a response to severe critical
illness, such as trauma, septicaemia, massive
haemolysis, or severe megaloblastic anaemia.

52. Notes
When total WBCs count is normal , changes in
differential counts are of less significance as it
usually changed with any viral infection.
Also when there is no anemia ,RBCs indices are
less significant .