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