Transcript CBC

Complete Blood Count (CBC)
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Panel of tests that examine different
components of the blood.
CBC values
RBC count
Hemoglobin
Hematocrit
RBC indices
WBC count and differential
Platelet count
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White Blood Count (WBC): actual number of white
blood cells per volume of blood.
WBC differential: types of WBC present.
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Red Blood Cells (RBC): actual number of red
blood cells per volume of blood
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Hemoglobin (Hb): amount of the oxygen carrying
protein in the blood
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Platelets (PLT): actual number of platelets per volume
of blood
• Mean Corpuscular Volume (MCV ):
a measurement of the average size of RBCs
• Mean Corpuscular Hemoglobin (MCH ): the
average
amount of oxygen-carrying hemoglobin
inside a RBC
• Mean Corpuscular Hemoglobin
Concentration
(MCHC): the average
concentration of hemoglobin
inside a RBC
• Red Cell Distribution Width (RDW): a variation in
the size of RBCs
The significance of CBC
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Find the cause of symptoms such as fatigue,
weakness, fever, bruising, or weight loss
Diagnosis of anemia
Estimation of blood loss
Diagnosis of polycythemia
Find an infection
Diagnosis of blood diseases as leukemia
Response to drug or radiation treatment
Screening before surgery
Abnormal count of certain types of cells
Principle
• The counting of the cellular elements of the blood
(erythrocytes, leukocytes, and platelets) is based on
the classic method of electrical impedance.
• Electrical resistant principle, which depend on the
fact that blood cells are non conductive to electricity,
so when they pass through electrical field they will
increase the electrical resistance.
• The counting chamber consists of a beaker, two
electrodes with a direct current, an orifice with
specified dimension; when suspended cells passes
through the aperture it will increase the electrical
impedance between the two electrodes, manifested as
a pulse (sum of pulse= count). The pulse height
indicate cell volume.
Performance
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The aspirated whole blood specimen is divided into two aliquots
and mixed with an isotonic diluent.
The first dilution is delivered to the RBC aperture bath, and the
second is delivered to the WBC aperture bath.
In the RBC chamber, both the RBCs and the platelets are
counted and discriminated by electrical impedance
Particles between 2 and 20 fL are counted as platelets, and those
greater than 36 fL are counted as RBCs.
Red cell histograms: histograms are derived by plotting the size
of each red cell on x axis and the relative number on the y axis.
They are used to determine the average size, distribution of size,
and to detect sub populations.
Histograms
Hb measurement
• A reagent to lyse RBCs and release hemoglobin is added to the
WBC dilution before the WBCs are counted by impedance After
the counting cycles are complete, the WBC dilution is passed to
the hemoglobinometer for hemoglobin determination (light
transmittance read at a wavelength of 535 nm).
• Hemoglobin, on most automated systems, is measured as
cyanmethemoglobin.
• Red cells are lysed and potassium ferricyanide oxidizes
hemoglobin to methemoglobin, which combines with potassium
cyanide forming cyanmethemoglobin.
• The brown color is measured spectrophotometrically and the
corresponding hemoglobin reported.
• Normal rang
 Males 14-18 g/dl
 Females 12-16 g/dl
• Normal blood contains about 15-16 grams hemoglobin per 100
ml (dL).
• Each gram of hemoglobin can carry about 1.35 ml of gaseous
oxygen.
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Fully saturated arterial blood will therefore contain about 20 ml
of oxygen per 100 cc .
• The relative amount of oxygen in the blood compared to the
carrying capacity of the hemoglobin is called the oxygen
saturation, and is expressed as a percentage.
Hematocrit
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Hematocrit is the volume of the red cells as compared
to the volume of the whole blood sample.
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Hematocrits on the automated systems are calculated.
– Calculated: (MCV)×(RBC) = Hct
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Usually expressed in percentage (42%)
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Males 42-52 %
Females 37-47% (pregnant>33%)
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Provides information on the amount of red blood
cells (RBC) present in the blood.
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Decreased levels means anemia from hemorrhage,
parasites, nutritional deficiencies or chronic disease
process, such as liver disease, cancer, etc.
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Increased levels are often seen in dehydration or
polycythemia
Red Blood Cell Count (RBC)
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Normal value = 4.6 to 6.2 x 106 cells/L
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Decreased with anemia
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Increased with erythrocytotic states such as
polycythemia vera, erythrocytosis of chronic
hypoxia, dehydration, stress polycythemia, and
thalassemia minor.
MCV
• Mean cell volume
• MCV is average size of RBC
• MCV =
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Hct x 10
RBC (millions)
If 80-100 fL, normal range, RBCs considered
Normocytic
If < 80 fL are Microcytic
If > 100 fL are Macrocytic
• Not reliable when have marked anisocytosis
MCH
• MCH is average weight of hemoglobin per RBC.
• MCH =
Hgb x 10
RBC (millions)
MCHC
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MCHC is average hemoglobin concentration per RBC
MCHC = Hgb x 100
Hct (%)
If MCHC is normal, cell described as Normochromic
If MCHC is less than normal, cell described as
Hypochromic
There are no Hyperchromic RBCs
RDW
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An index of RBC size variation
May be used to quantitate the amount of anisocytosis on
peripheral blood smear
Normal range is 11.5% to 14.5% for both men and
women.
MPV: The MPV is a measure of the average volume of
platelets in a sample and is analogous to the erythrocytic
MCV.
Pct : analogues to HCT for RBCs
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Use of RBC indices in differential diagnosis can
provide picture of what is occurring clinically.
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If anemia caused be bone marrow failure, requires
information about RBC production. Information
obtained from reticulocyte count. Reticulocyte
count measures effective RBC production.
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As study different anemias, will learn morphology.
Red Cells Histogram
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Noramal red cell histogrem
dispays cells form (36- 360 )
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(24- 36 fl ) flag may be due
1- RBCs fragments
2- WBCs fragments
3- Giant plts
4- Microcyte
Shift to right :
- Leukemia
- Macrocytic anemia
- Megaloblastic anemia
 Shift to left :
- Microcyic anemia (IDA)
 Bimodal
- Cold agglutinin
- IDA, megaloblastic anemia with transfusion.
-Saidroblastic anemia.
 Trimodal
Anemia with transfusion
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Platelet Count
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Normal Range = 150 to 450 x 103 cells/L
Thrombocytosis
– inflammatory disorders
– myeloproliferative states
– acute blood loss
– hemolytic anemias
– carcinomatosis
– status post-splenectomy
– exercise etc.
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Thrombocytopenia
– Production defects such as aplastic anemia, marrow
replacement, megaloblastic and severe iron
deficiency anemias, uremia etc.
– Consumption defects with autoimmune
thrombocytopenias, DIC, hypersplenism, massive
hemorrhage and many severe infections.
Plts histogram
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Normal Rang (2-20 fl)
(0-2)
1- Air Babbles
2- Dust
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Over 20 fl
1- Microcyte
2- Scishtocyte
3- WBCs fragments
4- Giant Plts
5- Clumped plts
Reticulocytes
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Useful in determining response and potential of bone
marrow.
Reticulocytes are non-nucleated RBCs that still contain
RNA.
Visualized by staining with supravital dyes, including
new methylene blue; RNA is precipitated as dyeprotein complex.
Normal range is 0.5-2.0% of all erythrocytes.
If bone marrow responding to anemia, should see
increases in Retic count.
Newborns have higher Retic count than adults until
second or third week of life.
Reticulocytes
Sickle cells (Dreprnocytes)
A variation in erythrocyte distribution such as
rouleaux formation or agglutination
White Blood Cell Count (WBC)
The white blood cell differential count determines the number of
each type of white blood cell, present in the blood.
 It can be expressed as a percentage (relative numbers of each
type of WBC in relationship to the total WBC) or as an absolute
value (percentage x total WBC). Of these, the absolute value is
much more important than the relative value.
There are five basic white blood cell types:
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Neutrophils
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Eosinophils
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Basophils
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Lymphocytes
 Monocytes
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Each WBC cell type has its' own unique features.
Neutrophils
Polymorphonuclear Neutrophils
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These are the most common of the WBCs and
serve as the primary defense against infection.
The typical response to infection or serious injury
is an increased production of neutrophils.
Bands/Stabs
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Early in the response to infection, immature forms of
neutrophils will be seen. These are call Stab or Band
cells.
The presence of these immature cells is called a "shift to
the left" and can be the earliest sign of a WBC response,
even before the WBC becomes elevated.
Eosinophils
These cells play a role in allergic disorders and in combating
parasitic infections.
 Elevations in eosinophil counts are associated with:
 Allergic reactions
 Parasite infections
 Chronic skin infections
 Some cancers
 Decreases in eosinophil
counts are associated with:
 Stress
 Steroid exposure
 Anything that may suppress WBC production generally
Basophils
These cells can digest bacteria and other foreign bodies (phagocytosis)
and also have some role in allergic reactions.
 Elevations in basophil counts are associated with:
 Some cancers
 Some allergic reactions
 Some infections
 Radiation exposure
 Diminished basophil
counts are associated with:
 Stress reactions
 Some allergic reactions
 Hyperthyroidism
 Prolonged steroid expo
Monocytes
These cells respond to inflammation, infection and foreign bodies by
ingesting and digesting the foreign material.
 Increased monocyte counts are associated with:
 Recovery from an acute infection
 Viral illness
 Parasitic infections
 Collagen disease
 Some cancers
 Decreased monocyte
counts are associated with:
 HIV infection
 Rheumatoid arthritis
 Steroid exposure
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Some cancers
Lymphocytes
These cells play both an immediate and delayed role in response to infection or
inflammation.
 Increased numbers of lymphocytes are seen in:
 Most viral infections
 Some bacterial infections
 Some cancers
 Graves' disease
 Decreased numbers of
lymphocytes are seen in:
 Steroid exposure
 Some cancers
 Immunodeficiency
 Renal failure
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Lupus
White Blood Cell Count (WBC)
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The lysing reagent also cause WBCs membrane collapse
aruond the nucleus , so the counter actually measuring the
nuclear size.
Cells lies between
• (35-90 fl) are considered lymphocyte.
• (90-160 fl) are considered MID cells
• (160-450 fl) are neutrophile.
Definition of Anemia
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Inability of blood to supply tissues with adequate
oxygen for proper metabolic function.
Usually associated with decreased levels of hemoglobin
or hematocrit (packed red cell volume)
Usually associated with decreased RBCs.
Diagnosis made by patient history, physical
examination, signs and symptoms, and hematological
laboratory findings.
Classified as moderate (Hb 7-10 g/dl) or severe (Hb
<7g/dl).
Two general forms of anemia: Absolute Anemia
(decrease in red cell mass) and Relative Anemia
(increased plasma volume gives appearance of anemia).
RBC and Hemoglobin Production
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In healthy individuals, about 1% of RBCs lost daily.
Bone marrow continuously produces RBCs to equal
daily loss.
Reticulocyte count is a lab measurement of this loss.
Normal Retic count is 0.5-2.0% of circulating RBCs.
Replacement requires functioning bone marrow,
normal RBC maturation and ability to release mature
RBCs to peripheral blood.
Proper nutrition required (B12, Folate). Also requires
normal hemoglobin synthesis.
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Erythropoietin levels (Epo) useful diagnostic tool.
Erythropoietin is a hormone produced in the kidney.
Levels of erythropoietin varies with oxygen tension in
kidney tissues (↓ Oxygen -↑ Epo, and vice versa).
Anemic people usually respond by increasing
erythropoietin levels.
Clinical Diagnosis
Made by combination of factors including: patient
history, physical signs and changes in hematologic
profile (CBC).
Signs and symptoms usually non-specific: fatigue,
weakness, shortness of breath - especially after
exertion.
Functional classification of Anemias
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Decreased RBC production (hypoproliferative)
– Defective hemoglobin synthesis
 Fe deficiency
 B12 deficiency
 Folate deficiency
 Impaired bone marrow or stem cell function, as in
leukemia
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Increased RBC destruction, as in sickle cell anemia or hemolytic
anemia
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Combination of the two (sometimes called “ineffective
erythropoiesis”)
Decreased MCV and Decreased MCHC
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Microcytic/ Hypochromic Anemia
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Iron deficiency
Thalassemia
Anemia of chronic disease
Sideroblastic anemia
Lead poisoning
Increased MCV, Decreased MCHC
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Macrocytic/ Normochromic Anemia
Folate deficiency
B12 deficiency
Hypothyroidism
Iron Deficiency Anemia
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Iron metabolism
– Absorption in duodenum
– Transferrin transports iron to the cells.
– Ferritin and hemosydrin store iron.
10% of daily iron is absorbed
Most body iron is present in hemoglobin in circulating red cells
The macrophages of the reticuloendotelial system store iron
released from hemoglobin as ferritin and hemosiderin
Small loss of iron each day in urine, faeces, skin and nails and in
menstruating females as blood (1-2 mg daily)
Introduction
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Heritable, hypochromic anemias-varying degrees of
severity
Genetic defects result in decreased or absent
production of mRNA and globin chain synthesis
At least 100 distinct mutations
High incidence in Asia, Africa, Mideast.
Globin Chains
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Alpha Globin
– 141 amino acids
– Coded for on Chromosome 16
– Found in normal adult hemoglobin, A1 and A2
Beta Globin
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Delta Globin
Found in Hemoglobin A2--small amounts in all adults
Gamma Globin
– Found in Fetal Hemoglobin
Zeta Globin
– Found in embryonic hemoglobin
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146 amino acids
Coded for on Chromosome 11, found in Hgb A1
Hemoglobin Types
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Hemoglobin Type
Hgb A1—92%--------Hgb A2—2.5%-------Hgb F — <1%--------Hgb H -----------------Bart’s Hgb-------------Hgb S-------------------Hgb C-------------------
Globin Chains
 a2b2
 a2d2
 a2g2
 b4
 g4
gluval
 a2b26
glulys
 a2b26
Alpha Thalassemias
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Result from gene deletions
One deletion: Silent carrier; no clinical significance
Two deletions: a Thal trait; mild hypochromic
microcytic anemia
Three deletions: Hgb H; variable severity, but less
severe than Beta Thal Major
Four deletions: Bart’s Hgb;
Usually no treatment indicated
4 deletions incompatible with life
3 or fewer deletions have only mild anemia
Beta Thalassemias
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Result from Point Mutations on genes
0
– b -no b-globin synthesis;
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– b reduced synthesis
Disease results in an overproduction of a-globin chains,
which precipitate in the cells and cause splenic
sequestration of RBCs
Erythropoiesis increases, sometimes becomes
extramedullary