1. INTRO TO HEMATOLOGY Flashcards
It is the science of blood or study of blood cells.
Hematology
greek word that means blood
haima
greek word that means study or science
logos
It deals with the study of normal and abnormal development, physiology, function and death or destruction or formed elements of blood.
Hematology
two main parts of blood
Liquid portion
Formed elements
Function of Blood (Rodak’s)
- transport O2 from lungs to tissues
- clears tissues of CO2
- transports glucose, proteins, lipids
- moves waste to liver and kidneys
average human or healthy individual amount of blood in the body
5L of blood
Formed Cells
RBC
WBC
Platelets
anucleate, biconcave, discoid cells filled with hemoglobin
transport O2 and CO2
Erythrocytes
color of the RBC
pink to red (salmon pink)
measurement of the diameter RBC
6-8 micrometer (7-8)
reason for the biconcave shape of RBC
central pallor (1/3 of the cell)
Why is RBC biconcave?
It cannot carry out O2-CO2 exchange function effectively if not biconcave
protect host from infection and injury/ inflammatory
Leukocytes
Types of WBCs:
Granulocytes
Agranulocytes
liquid portion of blood
plasma
they provide coagulation enzymes that protect vessels from trauma and maintain circulation and transport and nourish blood cells
plasma
Described “worms” in blood
Athanasius Kircher (1657)
Gave an account of RBCs
Anton van Leeuwenhoek (1674)
Described platelets as “petites plaques”
Giulio Bizzozero (1800s)
Developed the Wright stain
James Homer Wright (1902)
polychromatic, a mixture of acidic and basic dyes, remains the foundation of blood cell identification
Wright’s Romanowsky-type stain
the scientific term for cell appearance
morphology
cell morphology encompasses what parameters:
cell color, size, shape, cytoplasmic inclusions, nuclear condensation
what disorders can be detected by counting RBCs?
anemia or polycythemia
characterized by loss of O2-carrying capacity and is often reflected in a reduced RBC count or decreased Hgb concentration
Anemia
characterized by an increased circulating RBC mass which leads to hyperviscosity
Polycythemia
historically, microscopists counted RBCs by: (steps)
- pipette a tiny aliquot of blood
- mix with 0.85% normal saline
- diluted blood is transferred in a hemacytometer
- microscopist observe and count RBCs in selected area of the hemacytometer
- a mathematical formula is applies based on dilution and area on the hemacytometer counted
- the count is reported
why is normal saline used in the dilution of blood for RBC count
normal saline matches the osmolality of blood
dilution ratio used in counting RBCs
1:200
Pipette used in RBC count
thoma pipette
RBCs can be reported using these units:
per microliter (mm3), milliliter (cc), liter (L)
was developed before the 1900s and was the only way to count RBCs till 1958
visual RBC counting
First electronic counter patented in 1953
Coulter Counter
patented the coulter counter
Joseph and Wallace Coulter of Chicago, Illinois
it is the coulter principle that is used to count RBCs in many automated blood analyzers
direct current electrical impedance
a reddish protein found inside RBCs
hemoglobin
Hgb measurement relies on a weak solution of ___________ and _____________
potassium cyanide and potassium ferricyanide
a weak solution of potassium cyanide and potassium ferricyanide is also called:
Drabkin reagent
process of hemoglobin measurement: (steps)
- an aliquot of whole blood is mixed with a measured volume of Drabkin reagent
- Hemoglobin is converted to stable cyanmethemoglobin
- color intensity is measured using a spectrophotometer
- the color intensity is mathematically converted to hemoglobin concentration
Wavelength used in cyanmethemoglobin method?
540 nm
some blood cell analyzers replace cyanmethemoglobin with a formulation of the ionic surfactant (detergent) _________________________ to reduce environmental cyanide.
sodium lauryl sulfate
it is the ratio of the volume of packed RBCs to the volume of whole blood
hematocrit
other term for hematocrit
packed cell volume
process of hematocrit determination: (steps)
- Transfer blood to a plastic tube with uniform bore
- Centrifuge
- Measure the column of RBCs
- Divide the total length of the column of RBCs + plasma; the normal ratio approached 50%
uses the three results of RBC count, Hgb, and Hct to be computed
RBC Indices
(Indices) reflect RBC diameter on a Wright-stained blood film
Mean Cell Volume
(Indices) reflects RBC staining intensity and amount of central pallor
Mean Cell Hemoglobin Concentration
(Indices) mass of hemoglobin per cell and parallels the MCHC
Mean Cell Hemoglobin
(Indices) degree of variation in RBC volume
Red Cell Distribution Width
extreme variation of blood cell volume
anisocytosis
MCV is recorded in? (unit)
femtoliters
MCHC is expressed in? (unit)
grams/deciliter
MCH is expressed in? (unit)
picograms
are blood cells that are newly released from the RBC production site: the bone marrow
Reticulocytes
other term for reticulocytes
Polychromatophilic erythrocytes
In the Wright-stained blood film, reticulocytes compose (percentage) of RBCs exceed the (measurement) average diameter and stain slightly (color).
0.5-2.5%; 7-8 mcm; blue-gray
are used to differentiate young red blood cells
methylene blue dyes
why are reticulocytes closely observed?
indicate the ability of the bone marrow to increased RBC production in anemia caused by blood loss or excessive RBC destruction
an especially sensitive measure of RBC production
immature reticulocyte fraction
RTC counts that are provided by fully automated blood cell analyzers
relative reticulocyte percentage, absolute reticulocyte count, immature reticulocyte fraction
Loosely related category of cell types dedicated to protecting their host from infection and injury
WBC
why are WBCs named this way?
they are colorless in an unstained cell suspension
used dilution ratio in WBC count
1:20
diluent used in WBC count
dilute acid solution
why is a weak acid solution used as a diluent for WBC counting?
acid lyses the RBCs that would obscure the WBCs
term used for decreased WNC count
leukopenia
term used for an increased WBC count
leukocytosis
(WBCs) are phagocytic cells whose major purpose is to engulf and destroy microorganisms and foreign materials
Neutrophils
an increase in neutrophils and often signals bacterial infection
neutrophilia
decrease in neutrophils and has many causes, but certain medications or viral infections often cause it
neutropenia
(WBCs) Slightly less mature neutrophils with a nonsegmented nucleus in a U or S shape
Band neutrophils
increase in BANDs that signals bacterial infection
left shift
(WBCs) Cells with round, bright orange-red cytoplasmic granules filled with proteins involved in immune system regulation
Eosinophils
elevated EOs count in response to allergy or parasitic infection
Eosinophilia
WBCs) Cells with dark purple, irregular cytoplasmic granules that obscure the nucleus. These granules contain histamines and various other proteins.
Basophils
An elevated basophil count; it is rare and often signals a hematologic disease
Basophilia
(WBCs) On a Wright-stained blood film, are nearly round, are slightly larger than RBCs, and have round featureless nuclei and a thin rim of nongranular cytoplasm. Mount humoral and cell-mediated responses against foreign antigens
Lymphocytes
increased lymphocyte count and is associated with viral infections.
Lymphocytosis
decreased lymphocyte count and is associated with drug therapy or immunodeficiency
Lymphocytopenia
(WBCs) Blue-gray with fine azure granules, and a nucleus that is usually indented or folded.
Immature macrophage
Monocytes
increase in the number of monocytes
Monocytosis
most numerous cell distributed throughout the body
Macrophages
uncontrolled proliferation of a clone of malignant WBCs
leukemia
most common form of leukemia in adults
chronic lymphocytic leukemia
most common form of childhood leukemia
acute lymphoblastic leukemia
2 to 4 mm in diameter, round or oval, anucleate, slightly granular, true blood cells that maintain blood vessel integrity by initiating vessel wall repairs.
platelets
a series of cellular and plasma-based mechanisms that seal wounds, repair vessel walls, and maintain vascular patency
hemostasis
Uncontrolled platelet and hemostatic activation is responsible for:
deep vein thrombosis,
pulmonary emboli,
acute myocardial infarctions,
cerebrovascular accidents,
peripheral artery disease,
repeated spontaneous abortions
provides for easier identification of platelets that due to their small volume makes them hard to distinguish in a hemacytometer.
phase microscopy
an elevated value sometimes signal a regenerative bone marrow response to platelet consumption
mean platelet volume
elevated platelet counts that signal inflammation or trauma but convey modest clinical significance
thrombocytosis
is a rare, life-threatening, malignant condition characterized by extremely high platelet counts and uncontrolled platelet production.
Essential thrombocythemia
low platelet count, a consequence of drug treatment and may be life-threatening; may be accompanied by easy bruising and uncontrolled hemorrhage.
Thrombocytopenia
RBC parameters in a complete blood count
RBC Count
Hct
MCV
MCH
MCHC
RDW
RTC Count
WBC parameters in a complete blood count
WBC count
NEUT count: % and absolute
LYMPH count: % and absolute
MONO count: % and absolute
EO and BASO counts: % and absolute
platelet parameters in a complete blood count
PLT ct, MPV
an indication of the automated analyzer when one of the results is abnormal
Flag
blood film examination: (steps)
- prepare a wedge-prep blood film on a glass slide
- fix and stain using Wright or Wright-Giemsa
- microscopist performs an estimate of the WBC count and platelet count comparison with their respective analyzer counts, and investigates discrepancies.
- the microscopist systematically reviews, identifies, and tabulates 100 (or more) WBCs to determine their percent distribution.
- microscopist examines the morphology of WBCs, RBCs, and platelets by light microscopy for abnormalities of shape, diameter, color, or inclusions
the final arbiter for all cell identification
medical laboratory professional
Form the inner surface of the blood vessel, are seldom studied in the hematology laboratory
endothelial cells
endothelial cells are import in:
maintain normal blood flow, tethering platelets during injury, enable WBC diapedesis
dissolution of a clot
fibrinolysis
are collected and stained to analyze nucleated cells that are the immature precursors to blood cells
immunostaining
quantitative flow cytometers are based on this principle
coulter principle
what instruments are used for qualitative flow cytometers
laser-based instruments
are cytometers that are mechanically simpler but technically more demanding
qualitative flow cytometers
is indispensable to leukemia and lymphoma diagnosis
Qualitative flow cytometry laboratory
employed in bone marrow aspirate examination to find genetic errors
cytogenetics
Philadelphia chromosome is a translocation between c9 and 22 that is diagnostic of what blood cell disorder?
chronic myeloid leukemia
t(15;17) which is a translocation of C15 and 17 is diagnostic of what blood c ell disorder?
acute promyelocytic leukemia
phenotypically detects an inherited RBC enzyme deficiency causing episodic hemolytic anemia
Glucose-6-phosphate Dehydrogenase Assay
are used to detect and diagnose sickle cell anemia and other inherited qualitative hemoglobin abnormalities and thalassemias
Sickle cell solubility screening assay, hemoglobin electrophoresis, and HPLC
one of the oldest hematology tests, detects inflammation and roughly estimates its intensity
Erythrocyte Sedimentation Rate
why is analyses of nonblood body fluids always performed with a rapid turnaround time?
cells in these environments rapidly lose integrity