Practical Hematology Lab
- LAB 1 -
BLOOD CELLS COUNT
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.
When CBC is ordered
• CBC may be ordered when a person has any number
of signs and symptoms that may be related to disorders
that affect blood cells.
1.
2.
3.
4.
5.
When an individual has fatigue or weakness
infection
inflammation
bruising, or bleeding
a doctor may order a CBC to help diagnose the
cause and/or determine its severity.
6. When a person has been diagnosed with a disease
known to affect blood cells, a CBC will often be
ordered on a regular basis to monitor their condition.
Likewise, if someone is receiving treatment for a
blood-related disorder, then a CBC may be performed
frequently to determine if the treatment is effective.
7. Some therapies, such as chemotherapy, can
affect bone marrow production of cells. Some
medications can decrease WBCs count overall. A
CBC may be ordered on a regular basis to monitor
these drug treatments.
Parameters of CBC
The complete blood count, or CBC, lists a number of many
important values. Typically, it includes the following:
1. White blood cell count (WBC or leukocyte count)
2. WBC differential count
3. Red blood cell count (RBC or erythrocyte count)
4. Hematocrit (Hct)
5. Hemoglobin (Hbg)
6. Mean corpuscular volume (MCV)
7. Mean corpuscular hemoglobin (MCH)
8. Mean corpuscular hemoglobin concentration (MCHC)
9. Red cell distribution width (RDW)
10. Platelet count
11. Mean Platelet Volume (MPV)
White blood cells count (WBCs)
Evaluation of white blood cells, the cells that are part of the
body's defense system against infections and cancer and also
play a role in allergies and inflammation
• White blood cell (WBC) count is a count of the total number
of white blood cells in a person's sample of blood.
• The normal number of WBCs in the blood is 4,500-11,000
white blood cells per microliter (mcL).
• Neutrophils
40-75% of WBCs.
• Lymphocytes
20-45% of WBCs.
• Eosinophils
1-6% of WBCs.
• Monocytes
2-10% of WBCs.
• Basophils
0-1% of WBCs.
White Blood Cell Differential
• May or may not be included as part of the panel of
tests. It identifies and counts the number of the
various types of white blood cells present.
• May be done as part of or in follow up to CBC)
Leukopenia
Caused by :
• Bone marrow disorders or damage
• Autoimmune conditions as rheumatoid arthritis and
systemic lupus erthrymatosus (SLE)
• Severe infections (sepsis)
• Lymphoma or other cancer that spread to the bone
marrow
• Diseases of immune system (e.g.,HIV)
leukocytosis
Caused by :
• Infection, most commonly bacterial
• Inflammation
• Leukemia, Myeloprolifrtive disorders
• Allergies, asthma
• Tissue death (trauma, burns, heart attack)
• Intense exercise or severe stress
Erythrocyte count (RBCs)
• Evaluation of red blood cells, the cells that transport oxygen
throughout the body:
• Red blood cell (RBC) count is a count of the actual number
of red blood cells in a person's sample of blood.
• Normal RBC range is:
• Male: 4.7 to 6.1 million cells per microliter (cells/mcL)
• Female: 4.2 to 5.4 million cells/mcL
• Hemoglobin measures the amount of the oxygen-carrying
protein in the blood.
•normal values:
•13.0-18.0 g/dL in adult males
•11.5-16.5 g/dL in adult, non-pregnant females.
• Hematocrit measures the percentage of a person's blood
that consists of red blood cells.
• normal values (Hct):
• 0.40-0.52 in adult males
• 0.36-0.47 in adult females.
Decrease blood oxygen carrying
components (anemia)
• Acute or chronic bleeding
• RBC destruction (e.g., hemolytic anemia, etc.)
• Nutritional deficiency (e.g., iron deficiency, vitamin
B12 or folate deficiency)
• Bone marrow disorders or damage
• Chronic inflammatory disease
• Kidney failure
Increase blood oxygen carrying
components (polycythemia)
• Dehydration
• Lung (pulmonary) disease
• Kidney or other tumor that produces excess
erythropoietin
• Smoking
• Genetic causes (altered oxygen sensing, abnormality
in hemoglobin oxygen release)
• Polycythemia vera—a rare (malignant) disease
Red Blood Cell Indices
• Red blood cell indices are calculations that provide
information on the physical characteristics of the RBCs:
• Mean corpuscular volume (MCV) is a measurement of
the average size of RBCs.
• Mean corpuscular hemoglobin (MCH) is a calculation of
the average amount of oxygen-carrying hemoglobin inside
a red blood cell.
• Mean corpuscular hemoglobin concentration (MCHC)
is a calculation of the average percentage of hemoglobin
inside a red cell.
• Red cell distribution width (RDW), which may be
included in a CBC, is a calculation of the variation in the
size of RBCs.
Mean Corpuscular Volume (MCV)
The MCV indicates the average volume of the red blood
cells.
Volume of RBC in femtoliters (fl) / μl of blood
MCV =
1 μl = 109 fl
RBC / μl of blood
Hematocrit * 10
=
RBC count in millions
• Normal value for the MCV : 80~97 fl
(fl)
If the MCV is less than 80 fl, the RBCs are are smaller
than normal (microcytic); caused by iron deficiency
anemia or thalassemia, for example.
• If the MCV is greater than 97 fl, the RBCs are larger
than normal (macrocytic), for example in anemia
caused by vitamin B 12 or folate deficiency.
• If the MCV is within the normal range, the RBCs are
normocytic
Mean Corpuscular Hemoglobin
Concentration (MCHC)
• The MCHC is an expression of the average concentration
of hemoglobin in the red blood cells. It gives the ratio of
the weight of hemoglobin to the volume of the red blood
cells.
• MCHC =
Hemoglobin in g/dl
* 100 (to convert to %)
Hematocrit /dl
Hemoglobin * 100 %
=
Hematocrit
• Normal value for the MCHC : 32~36 %
•
An MCHC below 32% indicates hypochromia, that
may be when MCV is low which is seen in conditions
such as iron deficiency anemia and thalassemia.
• An MCHC above 36% indicates hyperchromia which is
seen in conditions where the hemoglobin is more
concentrated inside the red cells, such as autoimmune
hemolytic anemia, in burn patients, and hereditary
spherocytosis, a rare congenital disorder.and red blood
cells with a normal MCHC are termed normochromic.
Please note that an MCHC above 38% should not occur.
Mean Corpuscular Hemoglobin (MCH)
• The MCH indicates the average weight of hemoglobin in the red
blood cells.
• MCH =
=
Weight of hemoglobin in 1 μl of blood
Number of red blood cells in 1 μl of blood
Hemoglobin * 10
Red blood cell count in millions
(pg)
1 g = 1012 pg
1 ml = 103 μl
• Normal value for the MCH : 27~31 pg
• An MCH lower than 27 pg is found in microcytic anemia and also
with normocytic, hypochromic RBCs.
• An elevated MCH occurs in macrocytic anemia and in some cases
of spherocytosis in which hyperchromia may be present.
Red cell distribution width (RDW)
• RDW is an index of the variation of red cell size
(volume) in a specimen of blood
• RDW=
Size at 80% tile – size zt 20% tile
Size at 80% tile + size zt 20% tile
Normal range : 10 ± 1.5 %
• RDW=
S.D. of size distribution
MEAN size
Normal range : 13 ± 1.5 %
• Advantages of having RDW :
1. Recognize RBC abnormality from CBC
2. Assist in differential diagnosis
3. Following the course of a disease
An example of Complete Blood Count (CBC)
• Low value indicates uniformity in size of RBCs
• High value Indicates mixed population of small and large
RBCs; immature RBCs tend to be larger. For example, in
iron deficiency anemia or pernicious anemia, there is
high variation (anisocytosis) in RBC size (along with
variation in shape – poikilocytosis), causing an increase
in the RDW.
Plateletes
• Platelets, also called "thrombocytes", are blood cells
whose function (along with the coagulation factors) is to
stop bleeding. Platelets have no nucleus: they are
fragments of cytoplasm which are derived from
the megakaryocyte of the bone marrow, and then enter
the circulation.
• On a stained blood smear, platelets appear as dark
purple spots, about 20% the diameter of red blood cells.
The smear is used to examine platelets for size, shape,
qualitative number, and clumping. The ratio of platelets
to red blood cells in a healthy adult is 1:10 to 1:20.
Low platelet concentration is thrombocytopenia and is due to
either decreased production or increased destruction.
Elevated platelet concentration is thrombocytosis and is
either congenital, reactive (to cytokines), or due
to unregulated production: one of the myeloprolerative
neoplasms or certain other myeloid neoplasms. A disorder
of platelet function is a thrombocytopathy.
• Platelet concentration is measured either manually using
a hemacytometer, or by placing blood in an automated
platelet analyzer using electrical impedance, such as
a coulter counter.
• The normal range for platelets in healthy Caucasians is
150,000 to 400,000 per cubic millimeter
Increased Platelete Count
Known as thrombocytosis caused by :
• Cancer (lung, gastrointestinal, breast, ovarian,
lymphoma)
• Rheumatoid arthritis, inflammatory bowel disease,
lupus
• Iron deficiency anemia
• Hemolytic anemia
• Myeloproliferative disorder (e.g., essential
thrombocythemia)
Decreased Platelete Count
Known as thrombocytopenia caused by:
• Viral infection (mononucleosis, measles, hepatitis)
• Rocky mountain spotted fever
• Platelet autoantibody
• Drugs (acetaminophen, quinidine, sulfa drugs)
• Cirrhosis
• Autoimmune disorders
• Sepsis
• Leukemia, lymphoma
• Myelodysplasia
• Chemo or radiation therapy