Download Formed Elements and Associated Tests

Formed Elements and
Associated Tests
• Leukocyte or White Blood Cell (WBC)
Count
– Complete WBC count includes the total
number of all types of white blood cells
in a microliter of blood
– Normal WBC or leukocyte counts in
adults range from approximately 4.5 to
11 thousand/mm3
Formed Elements and
Associated Tests
• Leukocyte or White Blood Cell (WBC)
Count
– Elevated level usually indicates infection
– If grossly elevated, leukemia could be
the cause
Formed Elements and
Associated Tests
• Leukocyte or White Blood Cell (WBC)
Count
– Low level usually indicates a viral
infection or autoimmune deficiency
– Extreme bacterial infection also can
destroy enough white blood cells to
significantly reduce their numbers
Formed Elements and
Associated Tests
• Leukocyte or White Blood Cell (WBC)
Count
– Manual method is through use of
hemocytometer
– MAs require further training to perform
manual WBC count in a medical
laboratory
Formed Elements and
Associated Tests
• Differential White Blood Cell Count
– Determines the percentages of each
type of leukocyte in a given sample
– Most commonly performed by the
automated analyzer
Formed Elements and
Associated Tests
• Differential White Blood Cell Count
– Types of leukocytes that are counted are
neutrophils, eosinophils, basophils,
lymphocytes, and monocytes
– Results may be read as percentages or
as numbers in a given quantity
depending on the laboratory and
equipment being used.
count, (A) the slide is
examined under oil immersion.
(B) Cells are viewed using a
bright light and 100×
magnification.
FIGURE 48-13 Types of
white blood cells.
Preparing Slides
• Refer to Procedure 48-4: Preparing
Slides for details about this
technique.
• MAs require further training to
perform this test in a medical
laboratory; it is commonly performed
in an educational setting to further
understanding.
PROCEDURE 48-4
Preparing Slides
FIGURE A Blood smear.
PROCEDURE 48-4
(continued) Preparing
Slides
FIGURE B Blood smear.
PROCEDURE 48-4
(continued) Preparing
Slides
FIGURE C Blood smear.
PROCEDURE 48-4
(continued) Preparing
Slides
FIGURE D Blood smear.
(continued) Preparing
Slides
FIGURE E Wright’s
staining process.
(continued) Preparing
Slides
FIGURE F Wright’s
staining process.
(continued) Preparing
Slides
FIGURE G Wright’s
staining process.
(continued) Preparing
Slides
FIGURE H Wright’s
staining process.
Formed Elements and
Associated Tests
• Neutrophils
– Act as the body's primary defense and
make up the largest percentage of white
blood cells
– Granules are neutral in color on
laboratory-stained slides
Formed Elements and
Associated Tests
• Neutrophils
– Phagocytosis
• The process in which the neutrophil
surrounds, swallows, and digests the
bacteria
– Segmented
• Mature cells with a nucleus that is divided
into multiple segments connected by small
thin threads
Formed Elements and
Associated Tests
• Neutrophils
– Nonsegmented neutrophils
• Immature cells; also called stabs or bands
– Nicknamed a "shift to the left" and
indicates an early white blood cell
response
Formed Elements and
Associated Tests
• Neutrophils
– Tend to increase in response to
infection; may also increase from
hemorrhage, cancer, poisoning,
hemolysis, and inflammation
– Tend to decrease in response to a virus
or serious bacterial infection
FIGURE 48-14
Phagocytosis. The cell
engulfs and digests a
bacterium.
FIGURE 48-15 Band and
segmented neutrophils.
Formed Elements and
Associated Tests
• Eosinophils
– White blood cells assumed also to be
produced by the bone marrow
– A large number can indicate a parasitic
condition or the presence of certain
allergic conditions
– Have granules that produce a red color
on laboratory-stained slides
– Make up less than 3 percent of white
blood cell volume
Formed Elements and
Associated Tests
• Basophils
– Thought to be produced by the bone
marrow
– Produce heparin
– Increased amounts may be found in
patients who have had their spleen
removed or in patients with excessive
exposure to radiation.
Formed Elements and
Associated Tests
• Basophils
– Contain the vasodilator histamine
– Appear in tissues where an allergic
reaction is occurring
Formed Elements and
Associated Tests
• Basophils
– Concentration of basophils may
contribute to the severity of allergic
reactions
– Normal laboratory results generally
show basophils as less than 1 percent of
white blood cell volume.
Formed Elements and
Associated Tests
• Lymphocytes
– White blood cells produced in the bone
marrow and in the lymphoid tissue
– Primary function is to produce
antibodies against foreign substances
– Small and large, and can proliferate into
B and T cells
Formed Elements and
Associated Tests
• Lymphocytes
– B cells may convert into plasma cells
– T cells can produce helper cells,
cytotoxic cells, and suppressor cells
Formed Elements and
Associated Tests
• Lymphocytes
– Do not have granules and are
nonsegmented
– Make up the second largest volume of
white blood cells, comprising 25 to 30
percent
– To diagnose an individual with HIV,
testing is performed to evaluate the
type and amount of T cells present.
Formed Elements and
Associated Tests
• Monocytes
– White blood cells formed in the bone
marrow from stem cells; assist in
phagocytosis
– Ingest foreign particles or bacteria that
the neutrophils are unable to digest
– Assist in cleaning up cellular debris that
may have been left from the infection
Formed Elements and
Associated Tests
• Monocytes
– Increase is seen in patients with
tuberculosis, typhoid, and Rocky
Mountain spotted fever
– In a typical adult, make up 3 to 7
percent of the total white blood cell
volume
Formed Elements and
Associated Tests
• Platelets and Coagulation Studies
– Platelets (thrombocytes): the smallest
cells found in the blood; formed in the
bone marrow
– Live for about ten days and are
continuously reproduced
– Assist in the clotting of blood to stop
bleeding or assist in healing
Formed Elements and
Associated Tests
• Platelet Counts
– Typically between 150,000 and 400,000
platelets/mm3 in adults
– Testing is typically performed in an
outside laboratory or by automated
testing.
Formed Elements and
Associated Tests
• Platelet Counts
– Over 750,000 (thrombocytosis)
– Less than 50,000 (thrombocytopenia)
– Severely low counts can lead to internal
bleeding and even death
Formed Elements and
Associated Tests
• Prothrombin Time (PT, Protime)
International Normalized Ratio
(INR)/(PT/INR)
– PT
• coagulation test that measures the amount
of time it takes to form a clot
Formed Elements and
Associated Tests
• Prothrombin Time (PT, Protime)
International Normalized Ratio
(INR)/(PT/INR)
– INR
• Standard protocol that allows specimens
performed at different laboratories to have
consistent results
• Does not reveal specific bleeding disorders
in patients with liver failure or other
systemic diseases
Formed Elements and
Associated Tests
• Prothrombin Time (PT, Protime)
International Normalized Ratio
(INR)/(PT/INR)
– Typically used to screen patients with
symptoms of bleeding
– Protime for an average healthy adult will
show clotting at 10–14 seconds
– Higher than 30 seconds (or 4.5 INR)
indicates a risk for bleeding; more than
40 seconds is considered critical
Formed Elements and
Associated Tests
• Prothrombin Time (PT, Protime)
International Normalized Ratio
(INR)/(PT/INR)
– Elevated levels seen in patients with
severe bone marrow depression, cancer,
liver or collagen diseases, pancreatitis,
disseminated intravascular coagulation,
and toxic shock syndrome
Formed Elements and
Associated Tests
• Prothrombin Time (PT, Protime)
International Normalized Ratio
(INR)/(PT/INR)
– Decreased levels seen in patients with
myocardial infarction, multiple
myeloma, pulmonary embolus, or
thrombophlebitis
Formed Elements and
Associated Tests
• Partial Thromboplastin Time (PTT)
– Determines the length of time it takes
for a fibrin clot to form
– Can help to determine which specific
clotting factors are affected
– Commonly used to determine the
effectiveness of anticoagulant therapy
Formed Elements and
Associated Tests
• Partial Thromboplastin Time (PTT)
– Helps to screen for bleeding tendencies
and identify more precise causes
– Normal findings are typically 60–70
seconds.
Other Blood Tests
• Common panels include the lipid
panel and the liver panel
• Lipid panel
– Cholesterol, triglycerides, and highdensity lipoproteins (HDL)
• Liver panel
– SGOT and SGPT
• CBC
• Coagulation studies
Other Blood Tests
• Refer to the following tables in the
student text:
– Table 48-1: Common Blood Test Groups
– Table 48-2: Common Laboratory Tests
and Their Normal Values
– Table 48-3: Common Blood Chemistry
Tests
TABLE 48-1
Common
Blood Test
Groups
TABLE 48-2
Common
Laboratory
Tests and
Their Normal
Values
TABLE 48-3
Common
Blood
Chemistry
Tests
TABLE 48-3
(continued)
Common
Blood
Chemistry
Tests
TABLE 48-3
(continued)
Common
Blood
Chemistry
Tests
Other Blood Tests
• Comprehensive Metabolic Panel
(CMP)
– Screening tool used to:
• Evaluate organ function
• Check for common disorders
• Monitor the progress of current conditions
and response to medications
– Includes 14 essential tests included
among the basic metabolic panel, renal
panel, liver function tests, and
electrolytes
Other Blood Tests
• Comprehensive Metabolic Panel
(CMP)
– Abnormality in any area may indicate a
need for further, more-specific testing
– Recommended that the patient fast for
12 hours before testing
– Normal values can be found in Table 483 Common Blood Chemistry Tests
Other Blood Tests
• Glucose
– A simple sugar required by all body cells
to produce energy; circulates in the
blood
– Used to give energy to the cells
Other Blood Tests
• Glucose
– Hyperglycemia
• When glucose cannot get into the cells for
consumption, it builds up in the blood and
clogs up the organs
– Critical, life-threatening levels above
700 mg/dL while fasting
Other Blood Tests
• Glucose
– Hypoglycemia (low blood sugar)
• Can happen rapidly and can become lethal
before treatment may be considered
– Suspected blood glucose abnormalities
are always treated as if they are low,
until blood testing can be performed.