chapter 18 hematology. elsevier items and derived items © 2008 by saunders, an imprint of elsevier...

CHAPTER 18CHAPTER 18HEMATOLOGY

Elsevier items and derived items © 2008 by Saunders, an imprint of Elsevier Inc. 2

PRETESTPRETEST

True or False1. Plasma makes up approximately 55% of the blood

volume.

2. A mature erythrocyte is biconcave in shape and contains a nucleus.

3. Erythrocytes are responsible for defending the body against infection.

4. The life span of a red blood cell is 120 days.

5. The function of hemoglobin is to assist in blood clotting.


PRETEST, CONT.PRETEST, CONT.

True or False6. Leukocytosis is an abnormal increase in the

number of leukocytes.

7. Another name for a thrombocyte is a platelet.

8. A low hemoglobin reading occurs with polycythemia.

9. A neutrophil is classified as a granular leukocyte.

10. An increase in neutrophils occurs during an acute infection.


Content OutlineContent Outline

1. Hematology: the study of blood

a. Includes:• Morphologic appearance of blood cells

• Function of blood cells

• Diseases of the blood and blood-forming tissues

Introduction to Hematology


Introduction to Hematology, cont.


2. Laboratory analysis in hematology includes:

a. Purpose: Examining blood to detect pathologic conditions

b. Includes• Performing blood cell counts

• Evaluating clotting ability of blood

• Identifying cell types

c. Determines if each blood component falls within normal range




3. Specific hematology tests

a. Hemoglobin (Hgb or Hb)

b. Hematocrit (Hct)

c. White blood cell count (WBC)




d. Red blood cell count (RBC)

e. Differential white blood cell count (diff)

f. Erythrocyte sedimentation rate (ESR)

g. Platelet count (Plt)




4. Hematology tests

a. May be performed in the medical office

b. Automated blood analyzers designed for the medical office• Perform laboratory tests

– With accurate test results

– In a short period of time




• Operating manual

– Accompanies each analyzer

– Information included:

1) Operation

2) Test parameters

3) Care an maintenance




5. Complete blood count (CBC):

a. Most frequently performed hematologic test• Performed on new patients

• Performed on patients with a pathological condition




b. Tests included in a CBC:• White blood cell count (WBC)

• Red blood cell count (RBC)

• Platelet count

• Hemoglobin (Hgb or Hb)

• Hematocrit (Hct)

• Differential white blood cell count (diff)

• Red blood cell indices


Components and Function of Blood


1. Blood consists of two parts:

a. Plasma: liquid portion• Consists of clear yellowish fluid

• Makes up 55% of blood volume




• Function of plasma:

– Transports nutrients to tissues of body

– Picks up wastes from tissue: excreted through kidneys

– Transports: antibodies, enzymes, and hormones


Components and Function of Blood, cont.

Components and Function of Blood, cont.

b. Cells: solid portion• Erythrocytes

• Leukocytes

• Thrombocytes

– Makes up 45% of blood volume

2. Average adult body: 10 to 12 pints of blood


ErythrocytesErythrocytes

1. In an adult: erythrocytes formed in red bone marrow of

a. Ribs

b. Sternum

c. Skull

d. Pelvic bone

e. Ends of long bones of limbs


Erythrocytes, cont. Erythrocytes, cont.

2. Immature form: contains a nucleus

a. As RBC matures:• Loses nucleus as cell matures

• Acquires shape of biconcave disc

– Provides more surface area for exchange of substances



3. Red blood count range:

a. Adult female: 4 to 5.5 million/cubic mm of blood

b. Adult male: 4.5 to 6.2 million/cubic mm of blood



4. Hemoglobin

a. Makes up major portion of erythrocyte

b. Transports oxygen

c. Responsible for red color of RBC



d. Normal range:• Adult female: 12 to 16 g/dL

• Adult male: 14 to 18 g/dL

e. Hemoglobin molecule consists of:• Globin: protein

• Heme: iron-containing pigment



f. Transfer of oxygen and carbon dioxide:• Oxygen:

– Hemoglobin: picks up oxygen in the lungs

1) One Hgb molecule combines with 4 oxygen molecules

2) Oxyhemoglobin: hemoglobin that has combined with oxygen

a) Oxyhemoglobin is transported

and distributed to tissues

b) Oxygen released from the hemoglobin to tissues



• Carbon dioxide:

– Waste product

– Picked up from the tissues by the blood

– Transported to lungs and expelled



g. Arterial blood• Carries oxyhemoglobin

– Causes blood to have a bright red color



h. Venous blood• Lower oxygen content:

– Causes blood to have a dark red color



5. Average life span of RBC: 120 days

a. Hemolysis: breakdown of RBCs• RBC becomes fragile and ruptures

• Hemoglobin released from RBC


Erythrocytes, cont.Erythrocytes, cont.

– Hgb breaks down into:

1) Iron: stored and reused

2) Globin (protein): metabolized by body

3) Bilirubin:

4) Excreted as waste product in bile

a) Orange bile pigment

b) Produced by the breakdown of heme from the Hgb molecule

c) Transported to liver


LeukocytesLeukocytes

1. Clear, colorless cells that contain a nucleus

2. Adult normal range: 4,500 to 11,000/cubic mm of blood


Leukocytes, cont. Leukocytes, cont.

3. Leukocytosis: An abnormal increase in the number of leukocytes

a. Above 11,000/cubic mm of blood

4. Leukopenia: An abnormal decrease in the number of leukocytes

b. Below 4,5000/cubic mm of blood



5. Function of leukocytes: defend body against infection

a. Destroys invading pathogens

b. Removes them from the body

6. White blood cells (WBCs) do their work in the tissues

a. Transported to site of infection by circulatory system



7. During inflammation:

a. Blood vessels dilate in affected area• Results in increased blood supply

– More oxygen, nutrients, and WBCs delivered to infected area

– Aids in healing process



b. Cells making up capillary wall spread apart• WBCs squeeze through pores by ameboid

movement

• Move into tissues to fight infection

– Diapedesis: the movement of leukocytes through the pores of capillaries and into the tissues

– Ameboid movement: movement used by leukocytes that permits them to propel themselves from the capillaries into the tissues



8. Some white blood cells exhibit phagocytosis:

a. Engulf pathogens

b. Destroy pathogens


Leukocytes, cont.Leukocytes, cont.

c. Destroy damaged cells• Pus may form in infected area and consists of:

– Dead leukocytes

– Dead bacteria

– Dead tissue cells


ThrombocytesThrombocytes

1. Also known as platelets2. Small, clear, and shaped like discs3. Do not have a nucleus


Thrombocytes, cont. Thrombocytes, cont.

4. Formed in red bone marrow5. Function: participate in blood-clotting

mechanism6. Adult normal range: 150,000 to

400,000/cubic mm of blood


Hemoglobin DeterminationHemoglobin Determination

1. Hemoglobin (Hgb): major component of RBCs

2. Hgb transports oxygen to tissue cells3. Responsible for red color of RBCs


Hemoglobin Determination, cont.


4. Normal range

a. Adult female: 12 to 16 g/dL

b. Adult male: 14 to 18 g/dL

5. Hgb performed as individual test or as part of CBC




6. Decreased Hgb level occurs with:

a. Anemia (especially iron-deficiency anemia)

b. Hyperthyroidism

c. Cirrhosis of liver

d. Severe hemorrhaging




e. Hemolytic reactions

f. Certain systemic diseases• Leukemia

• Hodgkin's disease




7. Increased Hgb level occurs with:

a. Polycythemia

b. Chronic obstructive pulmonary disease

c. Congestive heart failure




8. Blood analyzer:

a. Most accurate and reliable method

b. Can use capillary or venous blood

c. Processes specimen in a short time

d. Results obtained while patient is still at office


HematocritHematocrit

1. Abbreviated Hct2. Hematocrit means "to separate blood"

a. Solid cellular elements separated from plasma• By centrifuging an anticoagulated blood

specimen

b. Heavier RBCs become packed and settle to bottom of tube


Hematocrit, cont. Hematocrit, cont.

c. Top layer: contains clear, straw-colored plasma

d. Between layers is small, thin, yellowish-gray layer• Buffy coat: contains platelets and WBCs



3. Purpose of Hct: measures percentage of packed RBCs in whole blood

4. Normal range

a. Adult female: 37% to 47%

b. Adult male: 40% to 54%



5. Low reading: may indicate anemia

6. High reading: may indicate polycythemia

7. Used with other tests to diagnose patient's condition



8. Microhematocrit method

a. Most often used in medical office

b. Blood obtained by skin puncture• Using a disposable capillary tube lined with

anticoagulant

c. Blood drawn into tube

- Sealed with a sealing compound



d. Centrifuged for 3 to 5 minutes• Packs the RBCs



e. Results read at top of packed cell column


What Would You Do?What Would You Not Do?



White Blood Cell CountWhite Blood Cell Count

1. Approximate measurement of number of WBCs in circulating blood

2. Adult normal range: 4,500 to 11,000 WBC/cubic mm of blood

a. Expressed as 4.5 to 11.0 (× 103/mm3) on laboratory reports


White Blood Cell Count, cont. White Blood Cell Count, cont.

4. Leukocytosis: increase in the number of WBCs (above 11,000)

a. Most commonly seen in acute infections:• Appendicitis

• Chickenpox

• Diphtheria

• Infectious mononucleosis

• Meningitis

• Rheumatic fever



b. Normal elevation can occur in:• Pregnancy

• Strenuous exercise

• Stress

• Treatment with corticosteroids



5. Leukopenia: decreased WBC

a. Viral infections

b. Chemotherapy

c. Radiation therapy



6. Blood cell counter used to determine WBC

a. Can also perform• RBC

• Platelet count

• Hemoglobin

• Hematocrit

• Differential WBC count

• Calculation of RBC indices


Automated Blood Cell CounterAutomated Blood Cell Counter


Red Blood Cell CountRed Blood Cell Count

1. Measurement of number of RBCs in whole blood

2. Normal range

a. Female: 4 to 5.5 million/cubic mm of blood• On laboratory report expressed as: 4.0 to 5.5 (x

106 mm3)

b. Male: 4.5 to 6.2 million/cubic mm of blood• On laboratory report expressed as : 4.5 to 6.2 (x

106 mm3)


Red Blood Cell Count, cont. Red Blood Cell Count, cont.

3. Performed using blood cell counter4. Decrease in red blood count

a. Anemia

b. Hodgkin's disease

c. Leukemia


Red Blood Cell Count, cont. Red Blood Cell Count, cont.

5. Increase in red blood count

a. Polycythemia

b. Dehydration

c. Pulmonary fibrosis


White Blood Cell Differential Count

White Blood Cell Differential Count

1. Five types of WBCs each having certain:

a. Appearance

b. Size

c. Shape

d. Function


White Blood Cell Differential Count, cont.

White Blood Cell Differential Count, cont.

2. Purpose of differential

a. To identify and count the five types of WBCs in a representative blood sample• Increase or decrease in one or more types

– Assists physician in making a diagnosis

3. Can be performed automatically or manually


Automatic MethodAutomatic Method

1. Blood cell counter used (e.g., Coulter counter)

2. Specimen requirement

a. Ethylenediaminetetraacetic acid–anticoagulated (EDTA-anticoagulated) blood specimen• Lavender-stoppered tube


Automatic Method, cont. Automatic Method, cont.

3. Blood cell counter automatically performs differential count

a. Prints results on a laboratory report


Differential Manual MethodDifferential Manual Method

1. Blood specimen can be made from:

a. Fresh whole blood (preferred)

b. EDTA-anticoagulated blood• Other anticoagulants alter:

– Morphology of WBCs

– Staining reaction of WBCs


Differential Manual Method, cont.


1. MA makes two blood smears

From Rodak BF: Hematology: clinical principles and applications, Philadelphia, 1995, Saunders.




3. Slides placed in protective container for transport to outside laboratory

4. Laboratory personnel stain smear (Wright's stain)

a. Because WBCs are clear and colorless

b. After staining:• Nucleus, cytoplasm, and granules: take

characteristic color of their cell type

– Aids in identification of the five different types of white blood cells




5. Minimum of 100 WBCs identified

a. Each assigned to appropriate category:• Neutrophils

• Eosinophils

• Basophils

• Lymphocytes

• Monocytes

From Custer RP: An atlas of the blood and bone marrow, ed 2, Philadelphia, 1974, Saunders.




6. Number of each type recorded as a percentage

a. Reflects overall distribution of WBCs in patient's blood


Types of White Blood CellsTypes of White Blood Cells

1. Classified into two categories

a. Granular: contain distinct granules in cytoplasm:• Neutrophils

• Eosinophils

• Basophils



Types of White Blood Cells, cont.


b. Nongranular: few or no granules in cytoplasm:• Lymphocytes

• Monocytes





2. Description of WBCs:

a. Neutrophils: 50% to 70%• Most numerous WBC

• Multilobed nucleus that stains purple

– May contain three to five lobes or segments




• Known as "segs"

• Cytoplasm: stains a faint pink

• Contains many fine granules: stain violet-pink

• Exhibit high degree of ameboid movement

• Function: actively phagocytic

– Phagocytosis: The engulfing and destruction of foreign particles such as bacteria




• Immature form: band

– Has a curved, nonsegmented nucleus

– Normal range: up to 5%

• Increase in neutrophils (and bands)

– Occurs during an acute infection




b. Eosinophils: 1% to 4%• Contain a segmented nucleus: of no more

than 2 lobes

• Cytoplasm: contains large granules

– Stain bright reddish-orange

• Increase in eosinophils:

– Allergic conditions

– Parasitic infestations




c. Basophils: up to 1%• Least numerous WBC

• Contains S-shaped nucleus

• Cytoplasm: contains large, coarse, dark bluish-black granules

– Almost completely obscure details of nucleus




d. Lymphocytes: 20% to 35%• Smallest WBC

• Round, slightly indented nucleus

– Almost completely fills cell

– Stains deep purplish blue




• Small rim of sky-blue cytoplasm around nucleus

– Contains few or no granules

• Involved with immune system and production of antibodies




• Increase occurs with viral diseases

– Infectious mononucleosis

– Mumps

– Chickenpox

– Rubella

– Viral hepatitis




e. Monocytes: 3% to 8%• Largest WBC

• Large nucleus

– Usually kidney or horseshoe shaped

– Can be round or oval

• Cytoplasm: stains grayish blue


Types of White Blood CellsTypes of White Blood Cells





3. Normal range for diff count:

a. Neutrophils 50% to 70%

b. Eosinophils 1% to 4%

c. Basophils up to 1%

d. Lymphocytes 20% to 35%

e. Monocytes 3% to 8%


POSTTESTPOSTTEST

True or False1. A function of the plasma is to transport antibodies,

enzymes, and hormones.2. The red bone marrow of the sternum produces red

blood cells in the adult.3. The normal range for a red blood cell count for an

adult female is 4 to 5.5 million.4. The normal range for hemoglobin for an adult

male is 12 to 16 g/dL.5. The normal adult range for a white blood cell

count is 4,500 to 11,000.


POSTTEST, CONT.POSTTEST, CONT.

True or False6. Leukocytes do their work in the tissues.7. Bilirubin is an orange pigment that comes from

the breakdown of hemoglobin.8. Leukopenia occurs when a patient has

appendicitis.9. An immature form of a neutrophil is known as a

seg.10. The primary function of a neutrophil is to form

antibodies.

chapter 18 hematology. elsevier items and derived items © 2008 by saunders, an imprint of elsevier...

Documents