Chapter 41
Hematology
© 2014 Cengage©Learning.
2014 Cengage
All Rights
Learning.
Reserved.
All Rights
May not
Reserved.
be scanned,
May not
copied
be scanned, copied
or duplicated, or or
posted
duplicated,
to a publicly
or posted
accessible
to a publicly
website,
accessible
in wholewebsite,
or in part.
in whole or in part.
Hematologic Tests
• Second most common type of tests
performed in POL
• Cellular components of blood affected
by changes in organs or tissues of body
© 2014 Cengage Learning. All Rights Reserved. May not be scanned, copied
or duplicated, or posted to a publicly accessible website, in whole or in part.
Hematologic Tests
•
•
•
•
Hemoglobin
Hematocrit
WBC count
Differential WBC
count
• RBC count
• RBC indices
• Platelet count
• Erythrocyte
sedimentation rate
(ESR)
• Prothrombin time
(PT)
© 2014 Cengage Learning. All Rights Reserved. May not be scanned, copied
or duplicated, or posted to a publicly accessible website, in whole or in part.
Hematologic Tests
• Tests provide valuable information for
diagnosis, evaluating patient’s progress,
regulating further treatment
© 2014 Cengage Learning. All Rights Reserved. May not be scanned, copied
or duplicated, or posted to a publicly accessible website, in whole or in part.
Hematologic Tests
• Complete blood count
–
–
–
–
–
Hemoglobin determination
Hematocrit determination
RBC count (and indices)
WBC count (and differential)
Platelet count
© 2014 Cengage Learning. All Rights Reserved. May not be scanned, copied
or duplicated, or posted to a publicly accessible website, in whole or in part.
Hematologic Tests
• Complete blood count
– Performed by manual testing procedures or
automated hematology analyzer
– Results recorded in patient’s medical record
– Accurate and timely documentation important
© 2014 Cengage Learning. All Rights Reserved. May not be scanned, copied
or duplicated, or posted to a publicly accessible website, in whole or in part.
Hemoglobin and Hematocrit Tests
• Hemoglobin
–
–
–
–
–
–
Major component of RBC
Carrier of oxygen and carbon dioxide in body
85% of dry weight of RBC
Synthesis of heme requires iron
Adult man requires 0.5 mg/day of iron
Menstruating woman requires 2 mg/day of iron
© 2014 Cengage Learning. All Rights Reserved. May not be scanned, copied
or duplicated, or posted to a publicly accessible website, in whole or in part.
Hemoglobin and Hematocrit Tests
• Hemoglobin
– Carries 95% of oxygen to cells
– Carries away 27% of carbon dioxide to lungs to be
expelled
– Acts as blood buffer
© 2014 Cengage Learning. All Rights Reserved. May not be scanned, copied
or duplicated, or posted to a publicly accessible website, in whole or in part.
Hemoglobin and Hematocrit Tests
• Hemoglobin
– Frequent hemoglobin disease is anemia
– Measured in POL using automated device
(HemoCue)
– Reference values vary according to both age and
sex
© 2014 Cengage Learning. All Rights Reserved. May not be scanned, copied
or duplicated, or posted to a publicly accessible website, in whole or in part.
Hemoglobin and Hematocrit Tests
• Hematocrit
– Packed RBC volume is ratio of volume of packed
RBCs to that of whole blood specimen
– Cellular components of blood sample separate
into layers when centrifuged at high speeds
• WBCs
• RBCs
• Plasma
© 2014 Cengage Learning. All Rights Reserved. May not be scanned, copied
or duplicated, or posted to a publicly accessible website, in whole or in part.
Hemoglobin and Hematocrit Tests
• Microhematocrit
– Centrifuge
Packed cell column showing
separation of cellular components >>
© 2014 Cengage Learning. All Rights Reserved. May not be scanned, copied
or duplicated, or posted to a publicly accessible website, in whole or in part.
White and Red Blood Cell Counts
• White blood cells and differential
– WBCs travel to tissues of body to find and destroy
pathogens
– Abscess: localized accumulation of pus
– Antibiotics are useful
– Normal values for WBCs vary with age
© 2014 Cengage Learning. All Rights Reserved. May not be scanned, copied
or duplicated, or posted to a publicly accessible website, in whole or in part.
Leukocyte Identification Guide
© 2014 Cengage Learning. All Rights Reserved. May not be scanned, copied
or duplicated, or posted to a publicly accessible website, in whole or in part.
White and Red Blood Cell Counts
• White blood cells and differential
– Granulocytes: contain granules within their
cytoplasm
• Neutrophils
• Basophils
• Eosinophils
– Leukocyte identified by contents of cytoplasm and
shape of their nuclei
– Agranulocytes: do not contain granules
© 2014 Cengage Learning. All Rights Reserved. May not be scanned, copied
or duplicated, or posted to a publicly accessible website, in whole or in part.
White and Red Blood Cell Counts
• White blood cells and differential
– Specialized protection methods
•
•
•
•
Phagocytosis
Detoxification
Inflammation
Immune response
© 2014 Cengage Learning. All Rights Reserved. May not be scanned, copied
or duplicated, or posted to a publicly accessible website, in whole or in part.
Red Blood Cells
• Erythrocytes carry oxygen to body’s
cells and bring back carbon dioxide
• Formed in bone marrow
• Varying sizes; round or slightly oval
shape
• Contains hemoglobin
© 2014 Cengage Learning. All Rights Reserved. May not be scanned, copied
or duplicated, or posted to a publicly accessible website, in whole or in part.
Platelets
• Platelets (thrombocytes)
• 140,000 to 400,000 per microliter of
blood
• Have no nuclei
• Involved in clotting of blood
(coagulation)
© 2014 Cengage Learning. All Rights Reserved. May not be scanned, copied
or duplicated, or posted to a publicly accessible website, in whole or in part.
Erythrocyte Indices
• Mean corpuscular (cell) volume (MCV)
• Mean corpuscular hemoglobin (MCH)
• Mean corpuscular hemoglobin
concentration (MCHC)
• Calculations that provide information
about size of RBCs and hemoglobin
content
© 2014 Cengage Learning. All Rights Reserved. May not be scanned, copied
or duplicated, or posted to a publicly accessible website, in whole or in part.
Erythrocyte Indices
• Blood parameters: RBC count,
hematocrit, hemoglobin
• Important in diagnosis or classification
and treatment of different types of
anemia
© 2014 Cengage Learning. All Rights Reserved. May not be scanned, copied
or duplicated, or posted to a publicly accessible website, in whole or in part.
Erythrocyte Indices
• Using erythrocyte indices to diagnose
– MCH and MCV increased in megaloblastic
anemias
– MCH and MCV increased in acute blood loss
anemia, chronic hemolytic anemias, aplastic
anemias, hypothyroidism, liver disease
– MCH and MCV decreased in hypochromic and
microcytic anemias and hyperthyroidism
© 2014 Cengage Learning. All Rights Reserved. May not be scanned, copied
or duplicated, or posted to a publicly accessible website, in whole or in part.
Erythrocyte Indices
• Using erythrocyte indices to diagnose
– MCHC increased in hereditary spherocytosis
– MCHC normal in macrocytosis
– MCHC decreased in iron deficiency anemia
© 2014 Cengage Learning. All Rights Reserved. May not be scanned, copied
or duplicated, or posted to a publicly accessible website, in whole or in part.
Erythrocyte Sedimentation Rate
• Measures rate at
which RBCs fall
toward bottom
when placed in
vertical tube >>
© 2014 Cengage Learning. All Rights Reserved. May not be scanned, copied
or duplicated, or posted to a publicly accessible website, in whole or in part.
Erythrocyte Sedimentation Rate
• ERS or “sed rate”
• Used in diagnosis and treatment of
many diseases
– Inexpensive
– Accurate
– Easy test to perform
© 2014 Cengage Learning. All Rights Reserved. May not be scanned, copied
or duplicated, or posted to a publicly accessible website, in whole or in part.
Erythrocyte Sedimentation Rate
• Wintrobe method
– EDTA venous blood sample mixed
– Blood transferred with Pasteur pipette to Wintrobe
tube
– No air bubbles
– Place tube vertically in rack to stand for 60
minutes
– Read number of millimeters red cells settled
– Normal values for Wintrobe method of ESR
© 2014 Cengage Learning. All Rights Reserved. May not be scanned, copied
or duplicated, or posted to a publicly accessible website, in whole or in part.
Erythrocyte Sedimentation Rate
• Westergren method
– Mix blood sample with 3.8% sodium citrate
solution before filling tube
– Normal values for Westergren method of ESR
– Sediplast ESR system
© 2014 Cengage Learning. All Rights Reserved. May not be scanned, copied
or duplicated, or posted to a publicly accessible website, in whole or in part.
Erythrocyte Sedimentation Rate
• Guidelines for
Wintrobe and
Westergren ESR
procedures to
measure accurate
results
Erythrocytes forming rouleaux
>>
© 2014 Cengage Learning. All Rights Reserved. May not be scanned, copied
or duplicated, or posted to a publicly accessible website, in whole or in part.
Erythrocyte Sedimentation Rate
• Using the ESR to screen
– ESRs increased in infections, acute stress,
inflammatory diseases, tissue destruction, other
conditions that lead to increase in plasma
fibrinogen
– Increased with menstruation, pregnancy, lupus,
malignant neoplasms, multiple myeloma
– With anemia, increases to severity of condition
– Decreased in polycythemia, spherocytosis, sickle
cell anemia
© 2014 Cengage Learning. All Rights Reserved. May not be scanned, copied
or duplicated, or posted to a publicly accessible website, in whole or in part.
C-Reactive Proteins
• CRP level rise and drop is quicker than
ESR
• Better inflammation indicator than ESR
• Helps in determining systemic
inflammatory conditions
• CRP made by liver
• hsCRP used in conjunction with lipid
profile and cardiac risk assessment
© 2014 Cengage Learning. All Rights Reserved. May not be scanned, copied
or duplicated, or posted to a publicly accessible website, in whole or in part.
Coagulation Studies
• Prothrombin time (PT)
– “Protime”
– Measures time it takes patient’s blood to clot
– Normal blood clots in 11-13 seconds
• International normalized ratio (INR)
– Can be universally applied
© 2014 Cengage Learning. All Rights Reserved. May not be scanned, copied
or duplicated, or posted to a publicly accessible website, in whole or in part.
Automated Hematology
• Advantages over manual methods:
–
–
–
–
Faster
Less expensive
Simple to operate
Accurate
• Instruments can be calibrated and lend
themselves to control testing; most
equipped with printers
© 2014 Cengage Learning. All Rights Reserved. May not be scanned, copied
or duplicated, or posted to a publicly accessible website, in whole or in part.
Automated Hematology
• Can calculate part or all of RBC indices
and print results
• Can be connected to other computers in
medical facility
© 2014 Cengage Learning. All Rights Reserved. May not be scanned, copied
or duplicated, or posted to a publicly accessible website, in whole or in part.
Automated Hematology
• Turn on machine and perform control
testing
• Always follow manufacturer’s instructions
© 2014 Cengage Learning. All Rights Reserved. May not be scanned, copied
or duplicated, or posted to a publicly accessible website, in whole or in part.