An Overview of Clinical Laboratory Hematology Flashcards
The average human possesses how many liters of blood.
5 liters
Liquid portion of the blood
Plasma
Functions of plasma
Provides coagulation enzymes; maintain circulation
Transports and nourishes blood cells
Three categories of blood cells
Red blood cells (RBCs), or erythrocytes
White blood cells (WBCs), or leukocytes
Platelets (PLTs), or thrombocytes
Study of blood cells
Hematology
Most common hematology test
Complete blood count (CBC)
Foundation method/stain for blood cell identification
Romanowsky stain
Giulo Bizzozero described platelets as
Petites plaque
The scientific term for cell appearance
Morphology
Characteristics of erythrocytes
Anucleated
Biconcave
Discoid
Reddish
Function of erythrocytes
Transports oxygen and carbon dioxide
Diameter of erythrocytes
7 to 8 um
The loss of oxygen-carrying capacity of RBC
Anemia
Anemia may be caused by
Reduced RBC count or decreased RBC hemoglobin concentration
Increased RBC count reflecting increased circulating RBC mass, a condition that leads to hyperviscosity
Polycythemia
History: Dilution ratio used for RBC counting
1:200
History: Glass pipette used to dilute RBCs for counting
Thomas pipette
Principle of Coulter counter
Direct current electrical impedance
Reagent used for hemoglobin measurement
Drabkin reagent
Ratio of the volume of packed RBCs to the volume of whole blood
Hematocrit
Normal ratio of hematocrit
50%
Hematocrit is also called
Packed cell volume (PCV)
Light-colored layer between the RBCs and plasma
Buffy coat
Composition of buffy coat
WBCs & platelets
RBC indices
Mean cell volume (MCV)
Mean cell hemoglobin (MCH)
Mean cell hemoglobin concentration (MCHC)
Volume measurement recorded in femtoliters (fL), reflects RBC diameter
Mean cell volume
Expressed in grams per deciliter (g/dL), reflects RBC staining intensity and amount of central pallor
Mean cell hemoglobin concentration
In picograms (pg) expresses the mass of hemoglobin per cell
Mean cell hemoglobin
Expresses the degree of variation in RBC volume
RBC distribution width (RDW)
Variation in size of blood cells
Anisocytosis
Microscope used to visually review RBC
Light microscope
Light microscope magnification to visually review RBC
500x or 1000x
RBC production site
Red bone marrow
Stain used to differentiate and count young RBCs
Methylene blue
Methylene blue is called
Nucleic acid stain or vital stain
Dyes absorbed by live cells
Supravital / vital stains
Young RBCs are called
Reticulocytes
Young RBCs contain:
Ribonucleic acid (RNA)
Cells dedicated to protecting their host from infection and injury
White blood cells
Dilution ratio used for counting WBCs
1:20
WBC diluent for counting
Dilute acid solution
Function of WBC diluent
Lyses RBCs for easier counting of WBCs
Decreased WBC count
Leukopenia
Increased WBC count
Leukocytosis
Stain used to differentiate WBC types
Wright stain
Color of the cytoplasm of neutrophils
Pink or lavender staining
Phagocytic cells whose major purpose is to engulf and destroy microorganisms and foreign material
Neutrophils
Decreased neutrophil count
Neutropenia
Increased neutrophil count
Neutrophila
Often cause of neutriphila or neutropenia
Medications or viral infections
Slightly less mature neutrophils with a nonsegmented nucleus in a U or S shape
Bands
Increased levels of bands signals
Bacterial infection
Cells with round, bright orange-red cytoplasmic granules filled with proteins involved in immune system regulation
Eosinophils
Increased levels of eosinophil
Eosinophilia
Eosinophila often signals
Response to allergy or parasitic infection
Cells with dark purple, irregular cytoplasmic granules that obscure the nucleus
Basophils
Elevated basophil count
Basophilia
Basophila often signals
Hematologic disease
Neutrophils, bands, eosinophils, and basophils are collectively called
Granulocytes
Complex system of cells that provide for host immunity
Lymphocytes
Functions of lymphocytes
Recognize foreign antigens and mount humoral (antibodies) and cell-mediated antagonistic responses
Distinguishing characteristics of lymphocytes
Round
Slightly larger than RBC
Round featureless nuclei
Thin rim of nongranular cytoplasm
Elevated lymphocyte count
Lymphocytosis
Lymphocytosis is often associated with
Viral infections
Abnormally low lymphocyte count
Lymphopenia or lymphocytopenia
Lymphopenia or lymphocytopenia is often associated with
Drug therapy or immunodeficiency
Immature macrophage passing through the blood from its point to a targeted tissue location
Monocytes
Most abundant cell type in the body
Macrophages
Function of macrophages
To identify and phagocytize foreign particles
Assist the lymphocytes in mounting an immune response through the assembly and presentation of antigen epitopes
Distinguishing characteristics of monocytes
Slightly larger than WBCs
Blue-gray cytoplasm
Fine azure granules
Indented or folded nucleus
Increased number of monocytes
Monocytosis
Benign monocytosis may be found in
Infections or inflammation
Decreased monocyte count
Monocytopenia
Uncontrolled proliferation of a clone of malignant WBCs
Leukemia
Methods used in the characterization of leukemias
Wright-stained bone marrow smears
Flow cytometric immunophenotyping
Molecular diagnostic technology
Cytogenetics
Cytochemical staining
Blood cells that maintain blood vessel integrity by initiating vessel wall repairs
Platelets or thrombocytes
Series of cellular and plasma-based mechanisms that seal wounds, repair vessel walls, and maintain vascular patency
Hemostasis
It is a process where neighboring platelets aggregate with one another and secretes proteins to form a plug
Thrombosis
Diameter of platelet
2 to 4 um
Characteristics of platelets
Round or oval
Anucleated
Slightly granular
Diseases associated with uncontrolled platelet and hemostatic activation
Deep vein thrombosis
Pulmonary emboli
Acute myocardial infarctions (heart attacks)
Cerebrovascular accidents (strokes)
Peripheral artery disease
Repeated spontaneous abortions (miscarriages)
Microscopy method for easier platelet identification
Phase microscopy
Advantage of automated blood cell analyzers
Ability to generate a mean platelet volume (MPV)
What does elevated mean platelet volume means
Signals a regenerative bone marrow response to platelet consumption
What does platelets do?
Responsible for normal blood vessel maintenance and repair
Elevated platelet counts
Thrombocytosis
What does thrombocytosis signify
Inflammation or trauma
Rare malignant condition characterized by extremely high platelet counts and uncontrolled platelet production
Essential thrombocythemia
Low platelet count
Thrombocytopenia
Thrombocytopenia is usually accompanied by
Easy bruising and uncontrolled hemorrhage
CBC specimen must be
Free of clots and hemolysis
Appropriate anticoagulant is used
Sufficient volume
Correct anticoagulant-to-blood ratio
Primary cause of incorrect anticoagulant-to-blood ratio
Insufficient volume / short draws
Registration of specimen in the work list is a process known as
Accession
Importance of accession
Reducing instances of identification error
Specialized, demanding, and fundamental CBC activity
Blood film examination
Stain used for blood film examination
Wright or Wright-Giemsa stain
Total magnification used for WBC count during blood film examination
400x or 500x
Total magnification used for platelet count during blood film examination
1000x
Process that systematically reviews, identifies, and tabulates 100 (or more) WBCs to determine their percent distribution
WBC differential count
Forms the inner surface of the blood vessels
Endothelial cells
Importance of endothelial cells
Maintaining normal blood flow
Decelerating platelets during times of injury
Enabling WBCs to escape from the vessel to the surrounding tissue
A key component of hemostasis
Platelets
Process of digesting clots to restore vessel patency
Fibrinolysis
These tests assess each portion of the coagulation pathway for deficiencies and are used to monitor anticoagulant therapy
Prothrombin time and partial thromboplastin time (or activated partial thromboplastin time)
Advanced hematology procedures
Bone marrow examinations
Flow cytometry immunophenotyping
Cytogenetic analysis
Molecular diagnosis assays
Assist physicians with bedside bone marrow collection
Medical laboratory scientists
Specimen collected to analyze nucleated cells that are the immature precursors to blood cells
Bone marrow aspirates and biopsy specimens
Precursor to RBCs
Cells of eryhtroid series
Myeloid series cells mature to form
Bands and neutrophils
Eosinophils
Basophils
Platelet precursor
Megakaryocytes
Increase in erythroid cell line indicates
Bone marrow compensation for excessive RBC destruction or blood loss
Stain used for biopsy specimen
Hematoxylin and eosin (H&E)
Cytochemical stains employed to differentiate abnormal myeloid, erythroid, and lymphoid cells
Myeloperoxidase
Sudan black B
Nonspecific and specific esterase
Periodic acid-Schiff
Tartrate-resistant acid phosphatase
Alkaline phosphatase
Principle of flow cytometers
Electrical impedance
Process of chromosome analysis
Cytogenetics
Reciprocal translocation between chromosomes 9 and 22
Philadelphia chromosome
Diagnostic of chronic myeloid leukemia
Philadelphia chromosome
Translocation between chromosomes 15 and 17
t(15;17)
Diagnostic of acute promyelocytic leukemia
t(15;17)
Process of phenotypically detects an inherited RBC enzyme deficiency causing episodic hemolytic anemia
Glucose-6-phosphate dehydrogenase assay
One of the oldest hematology test that detects inflammation and roughly estimates its intensity
Erythrocyte sedimentation rate (ESR)
Used to diagnose sickle cell anemia
Sickle cell solubility screening assay