Manual Hematology Methods Flashcards
Definition of Hematology
Study of cellular components of blood, cell ID, blood forming organs, blood related disorders, clotting mechanisms, lab tests
Definition of hemostasis
“Blood Balance”; a study of the mechanisms that the body employs to ensure balance and order in the circulatory system, coagulation system
Definition of Hematocrit
The percentage of packed red blood cells in a given volume of centrifuged blood; uses a small volume of blood in a capillary tube
Definition of Manual differential
Microscopically differentiate the white blood cells and note abnormalities, giving a percent of each type
Definition of a Buffy Coat
WBCs and platelets that form a layer on top of the RBCs after centrifugation
Definition of EDTA
Ethylenediaminetetraacetic acid, a powdered anticoagulant in lavender topped tubes, binds to Ca, gentle to cells
Definition of Na+ Citrate
Liquid anticoagulant, binds to Ca, 1:9 ratio (volume) is crucial
Definition of Zeta Potential
Charge on RBCs surface that keeps them from aggregating
Definition of Acute Phase Proteins
CRP, Fibrinogen
Definition of Rouleaux
A “stacking” of RBCs that occurs during the aggregation phase of ESR; and during certain infections
Definition of Trapped Plasma
Plasma stuck between RBCs in Hematocrit that cause a falsely increased reading
Microhematocrit Error Sources
Increased: trapped plasma (spun too slowly/not long enough, poikilocytosis)
Decreased: tissue fluids (edema), hemolysis, excess anticoagulants, bad clay seal
Microhematocrit Procedure
2 tubes with 3/4 EDTA/whole blood mix; seal end with clay; centrifuge; interpret on card, report avg. %
Phases of ESR
- Aggregation - RBCs form rouleaux
- Sedimentation - aggregates come out of sln
- Packing - aggregates pack together
ESR Procedure
1 ml EDTA/whole blood into well that contains .5 ml NaCl/Na Citrate; fill pipette to 0 mark with mix; leave in rack for hour; record mm’s of sedimentation
Causes of elevated ESR
- Room is too warm (extreme)
- Tilted tube
- Sample was agitated
ESR Ranges
Kids: 0-10 mm/hr
Men 50: 0-20 mm/hr
Women 50: 0-30 mm/hr
Non-error causes of elevated ESR
Inflamm. proteins lower zeta potential which lets cells aggregate/sediment more easily; from infections, autoimmune diseases, PID, pregnancy, and neoplastic diseases
Characteristics of a well-made smear
Length of smear should be 1/2 - 3/4 length of slide; edges should be contained within slide; no scratches/holes, a homogeneous spread; dark to light
Wright stain components
Wright stain for 2 min; then add diluted Giemsa stain for 4 min, looking for metallic sheen; wash with DI for 30 sec; allow to dry
Polychrome
Different colors, stains that will differentiate cell types
Peripheral smear examination steps
Scan at 10x looking for odd distribution of cells; at 40x find a good area; 100x stay in good area and preform evaluations
WBC Differential procedure
Count 100 WBCs using the 100X oil objective lens, use “battlement” pattern
Platelet estimation procedure
Scan the side at 100X and find the average number of platelets seen in 10 different fields then multiply this number by 15,000
Why do we use the “battlement” pattern?
Neutrophils tend to gather on the outside while lymphocytes tend to remain in the center
Neutrophil characteristics
Blue pink or tan cytoplasm
2 to 5 lobes connected with a thin filament
Band neutrophil characteristics
Blue pink or tan cytoplasm
C or S shaped nucleus, no individual lobes
Eosinophil characteristics
Pink cytoplasm with a high amount of red or orange granules and a segmented nucleus
Basophil characteristics
Light purple to colorless cytoplasm highly granular (dark blue or purple) segmented nucleus
Lymphocyte characteristics
Most variable type, round or oval shaped nucleus with dense chromatin which is roughly the size of a RBC, they can have small vacuoles and granules
On a slide they can have the ballerina skirt appearance
Monocyte characteristics
Extremely large nucleus with variable shape, blue-gray cytoplasm and varied cytoplasmic borders (they’re considered pseudopods) and they are vacuolated
Hemocytometer large square volume
0.1 ul
Hemocytometer small square volume
0.004 ul
Hemocytometer calculation formula
(# of squares counted)(Square volume)
= cells/mm3
CBC definition
Gives counts, sizes, maturities, shapes, hemoglobin content, and differentials for WBCs, RBCs, PLTs
Definition of VCS
Volume, conductivity, and light scatter used to analyze WBC differentials
Absolute count
The actual number of certain type of cell
Relative count
The percentage of a certain type of cell as compared to the total
Levy-Jennings chart
A visual representation of the performance of the analyzer, results of controls are recorded and plotted onto graphs
Definition of Delta check
An automatic check performed by the laboratory information system to notify the tech the significant differences between recent test results
Definition of quality assurance
Process of ensuring that the final results we report are correct, everything that we do to make sure our answers are right
Definition of quality control
Measures retake daily or during each shift during every test to ensure that the test is working properly and that our answers are right
RBC count ranges
Male: 4.5-5.5 x 10^6/ ul
Female: 4-5 x 10^6 ul
Hematocrit ranges
Male: 42-52%
Female: 36-46%
Hemoglobin ranges
Highest Hgb levels are found in newborns Male: 14.7-17.4 g/ul Female: 12-16 g/ul Critical values Male: >20 Females <7
Rule of three
RBC count x3 is roughly equal to hemoglobin +/- 3
Hemoglobin x3 is roughly equal to Hematocrit +/-3
“RBC x 3 = Hgb x 3 = Hct”
MCV range
Mean corpuscular volume
normal range 80-100fL
MCH range
Mean corpuscular hemoglobin normal range 28-34 pg
MCHC Range
Mean corpuscular hemoglobin concentration
normal range 32-36 g/dL
RDW range
Red cell distribution width
normal range 12-14.6%
WBC count ranges
Adult: 4.5-11 x 10^3/ul
Newborn: 9-30 x 10^3/ul
Critical high: >50 x 10^3/ul
Critical low: <1.5 x 10^3/ul
Neutrophil count ranges
Absolute: 1.8-7 x 10^3/ul
Relative: 40-80%
Lymphocyte count ranges
Absolute: 1-4.8 x 10^3/ul
Relative: 25-35%
Monocyte count ranges
Absolute: .1-.8 x 10^3/ul
Relative: 2-10%
Eosinophil count ranges
Absolute: 0-.4 x 10^3/ul
Relative:0-5%
Basophil count ranges
Absolute: 0-.2 x 10^3/ul
Relative: 0-1%
Band neutrophil count ranges
Absolute: 0-.7 x 10^3/ul
Relative: 0-5%
Platelet count range
150-450 x 10^3/ul
MPV range
Mean platelet volume
6.8-10.2 fL
Definition of the Coulter principle
Cells pass-through an aperture which momentarily impedes electronic flow allowing them to be counted and sized
Definition and testing methods of hemoglobin
Molecule inside RBCs that carries oxygen and CO2, ring with central Fe and Globin which combines with mRNA
Directly measured by the cyanmethemoglobin test methodology
Cyanomethemoglobin method
RBCs are lysed to release hemoglobin, potassium ferricyanide is added to make methemoglobin which combines with cyanide ions, solution is then measured with a spectrophotometer
VCS technology
Works like a flow cytometer, using current, radio waves, and laser beam.
Current: creates a pulse comparable to cell volume
Radio waves: penetrate cell mem and measure nucleus volume
Laser Beam: structure, shape, granularity, nuclear lobarity
MCV Equation
(HCT/RBC) x 10
MCH Equation
(HGB/RBC) x 10
Low will be hypochromic, cannot be too high since the amount of hemoglobin is limited by the size of the cell
MCHC Equation
(MCH/MCV) x 100
Relative values equation
Total WBC count
Correcting WBC count equation
# of nRBCs + 100
+++++
Results exceeds instrument linearity, too high of a value, dilute and re-run sample
“total voteout”, 2 of the 3 counts do not match, caused by a dirty aperture, clotted sample, or a short sample
…..
Incomplete computation, due to +++++ or —–
R flag
An abnormal result, check out patient history, then redraw if necessary
Definition of Shift
Sudden change in values that remains consistent
Definition of Trend
A gradual change in the same direction
Reticulocyte Calculation
1000 RBCs
= % Retics
Or:
# of Reticulocytes counted x 100
———————————————
RBC x 9
Corrected Reticulocyte Count
45%
= Correct Retic %
