Complete Blood Count (CBC)
The cellular components of blood are red blood cells, white
blood cells, and platelets, all of which are suspended in the plasma. The
complete blood count or CBC is a standard test to evaluate the status the
cellular components of your blood. A CBC is routinely done during treatment
-- especially prior to receiving any chemotherapy. The count is done with
automated equipment. The CBC is also used to check for anemia, infection and
Red Blood Cell Count (RBC) - The count of the
number of red blood cells per unit volume of blood. Red blood
cells (erythrocytes), are the most
numerous of the three cellular components of blood and normally make up almost half of
the blood's volume.
Hemoglobin(Hgb) indicates the amount of this
oxygen-carrying protein within red blood cells. Hemoglobin enables the RBCs
to carry oxygen from the lungs and deliver it to all body tissues. Oxygen is
consumed to provide energy to cells, leaving carbon dioxide as a waste
product, which the red blood cells carry away from the tissues and back to
the lungs. Red blood cells usually flow smoothly through the blood vessels.
A low hemoglobin value is indicative of
anemia. This may be the source of your fatigue or tired feeling. There are
many causes of anemia, but with prostate cancer, it might be due to the
cancer, chemotherapy treatments or hormone therapy. It is always wise
to check for iron deficiency anemia via a serum iron test and an total iron
binding capacity(IBC or TIBC). Iron deficiency anemia is well discussed at
www.nlm.nih.gov/medlineplus/ency/article/000584.htm. Another useful
measurement is mean corpuscular volume (MCV). MCV is a measurement of the average size
of your red blood cells (RBC). An elevated MCV occurs when your RBCs are
larger than normal (macrocytic), for example in anemia caused by vitamin
B12 deficiency. A low MCV, indicates your RBCs are smaller than
normal (microcytic), such as is seen in
iron deficiency anemia.
The Hematocrit(Hct) measures the proportion of red blood
cells to the total blood volume and is reported as a percentage.
What can I do if my RBC or Hgb are low?
and Epogen®) is sometimes administered by your
oncologist as an aid to alleviating anemia. This is an intramuscular
injection. Another drug used in the United States for low RBC is Aranesp®
(darbepoetin alfa) which has a longer half-life than epoetin alfa.
White blood cell count (WBC)
- The number of white blood cells in a specified volume of blood. White
blood cells form the mainstay of your immune system -- a low number might
increase your risk of infection and a high number possibly indicating that
you have an infection. Some chemotherapies increase the risk of 'immunosuppression" so oncologists set a lower limit to protect
you in the event this happens.
Differential white blood cell count - Percentages of the different types of white blood cells. There are five main types of white blood cells:
neutrophils (also called
granulocytes - GR and GR# in the table below),
White blood cells (leukocytes) are fewer in
number than RBCs, with a ratio of about 1 white blood cell to every 660 red blood
cells. White blood cells can adhere to and penetrate the sidewalls of blood
vessels as they wander about ready to fight infections. There are five main types of white blood cells that work together to
provide the body's major mechanisms for fighting infections, including the
production of antibodies. Neutrophils, also
called granulocytes because they contain enzyme-filled granules, are the
most prevalent white blood cell type. They help protect the body against
bacterial and fungal infections and ingest foreign debris. They consist of
two types: band (immature) and segmented (mature) neutrophils.
Oncologists pay particular attention to the absolute
neutrophil count (ANC)(which is also called the absolute granulocyte
count or AGC or GR# as many of the cytotoxic chemotherapy drugs decrease
the ANC, making patients more susceptible to infections. Most chemotherapy regimens require an absolute neutrophils count (GR and GR# in the table below) to be
≥ 1500 cells/μL.
Lymphocytes consist of two main types: T lymphocytes, which help
protect against viral infections and can detect and destroy some cancer
cells, and B lymphocytes, which develop into cells that produce antibodies
(plasma cells). Monocytes ingest dead or damaged cells and
provide immunologic defenses against many infective organisms.
Eosinophils kill parasites, destroy cancer cells, and are involved
in allergic responses. Basophils also participate in
What can I do if my WBC or GR# are low?
This is called neutropenia. A low
WBC can be treated with colony
stimulating factors (CSF). Examples of CSFs are G-CSF(granulocyte
colony-stimulating factor) - Neupogen® and GM-CSF(granulocyte
macrophage colony-stimulating factor) - Leukine®. These subcutaneously injected drugs may increase the WBC/GR# enough that
you can continue chemotherapy. Leukine is also sometimes given by I-V.
Another possibility is that your next chemotherapy treatment will be delayed
until your white blood cells recover.
Platelet count(Plt) - the number
of platelets in a specified volume of blood.
Platelets (thrombocytes) are the 3rd
cellular component of blood and are cell-like
particles smaller than red or white blood cells. As part of the blood's
protective mechanism for stopping bleeding, they gather at a bleeding site,
where they are activated. Once activated, they become sticky and clump
together to form a plug that helps seal the blood vessel and stop the
bleeding. At the same time, they release substances that help promote
clotting. The medline plus page at
additional information and links.
Thrombocytopenia is defined as a low platelet count(below
the lower limit of normal) and is called thrombocytopenia. Oncologists are
reluctant to treat patients with chemotherapy when the platelet count falls
below 100,000/μL, although treatment might be continued at lower values
depending on the patient. The panic level is < 25,000/μL.
Less commonly used CBC values are described below the table.
Here is an example of a
complete blood count panel for IMA Patient
Example of Complete
||4.0 - 10.4
||White Blood Cell count
||15.0 - 46.8
||% Lymphocytes in WBC
||1.8 - 12
||% Monocytes in
||45.5 - 79.7
||% Granulocytes in
|1.1 - 3.3
||0.1 - 0.8
||2.2 - 8.8
||4.36 - 5.78
||Red Blood Cell Count
13.8 - 17.3
||39.5 - 50.2
||81.0 - 95.0
||Mean corpuscular volume
||27.6 - 33.0
||Mean corpuscular hemoglobin
||32.8 - 36.4
||Mean corpuscular hemoglobin
||11.8 - 14.1
||Red cell distribution width
||141 - 320.0
||7.8 - 11.0
||Mean platelet volume
1. The highlighted entries focus on some of the more key values.
Note that there are many ways of reporting these values depending on the
units used. For example with platelets you might see any of these ways of
reporting the test results: thousands in a microliter of blood
(150,000/µL or 150.0x103/µL) or as millions in a liter of blood
platelet volume (MPV) is a machine-calculated measurement of the average
size of your platelets. New platelets are larger, and an increased MPV
occurs when increased numbers of platelets are being produced. MPV gives
your doctor information about platelet production in your bone marrow.
Mean corpuscular hemoglobin (MCH) is a calculation of the amount of
oxygen-carrying hemoglobin inside your RBCs.
Mean corpuscular hemoglobin concentration (MCHC) is a calculation of
the percentage of hemoglobin in the RBCs. Decreased values point to
hypochromasia, decreased oxygen- carrying capacity because of decreased
hemoglobin inside the cell. Hypochromasia is seen in iron deficiency
anemia and in
Red cell distribution width (RDW) is a calculation of the variation
in the size of your RBCs. This is useful in diagnosis of anemias such as
Low RBCs and Low WBCs(Neutropenia) -
Blood Cell Formation
Chemotherapy can cause
damage to other rapidly dividing cells while in the process of killing
Bone marrow is one such rapidly dividing cell that is responsible for producing red blood cells (RBCs), white
blood cells (WBCs) and platelets. This reduced activity of the bone marrow
is called myelosuppression.
White blood cells decrease most rapidly, because they have the shortest
life span. Red blood cells and platelets will decrease less rapidly under
the onslaught of chemotherapy.
Lymphocytes are a type of white blood cell and they are also produced in
the lymph nodes and spleen. The thymus gland, which is active only in
children and young adults, also produces and matures T lymphocytes.
The speed of blood cell production is controlled by the
body's need. When the oxygen content of body tissues or the number of red
blood cells decreases, the kidneys(90%) and liver(10%) produce and release
erythropoietin, a hormone that stimulates the bone marrow to produce more
red blood cells. The bone marrow produces and releases more white blood
cells in response to infections and more platelets in response to bleeding.
A single type of cell in the bone marrow, called a stem
cell, is the origin of red blood cells, white blood cells and platelet
cells. Stem cell division results in an immature red blood cell, white blood cell, or platelet-producing
cell (megakaryocyte). Division of the immature cell results in further
maturation giving rise eventually a red blood cell, white blood cells or
Author: Howard Hansen, 1/26/04