4. Laboratory Considerations Flashcards
Polychrome stains used to stain slides of peripheral blood and bone marrow
Wright or Wright-Giemsa (Romanowsky-type stains)
Fixative in Wright-Giemsa
Methanol
Cellular components stained by eosin
Basic elements:
- Hgb
- basic proteins
Cellular components stained by methylene blue
Acidic elements:
- cell nuclei
- immature cell cytoplasm
Counting chamber used for manual cell counting
Hemacytometer
Area of 1 square (out of 9 squares) of a hemacytometer
1 mm^2
Total volume accomodated by a hemacytometer
0.9 mm^3
Total area of a hemacytometer
9 mm^3
Volume of packed RBCs occupying a specific volume of whole blood
Hematocrit (Hct)
Hct is expressed in
- percentage
- liters per liter
Sample of blood used for retic counting
EDTA whole blood
Type of stain used in retic counting
Supravital stain
Stain used in retic counting
New methylene blue
Cellular constituents that take up the supravital stain
- RNA
- residual organelles
Ocular used in retic counting
Miller ocular
What is thprinciple used in sickle cell testing?
Difference of solubility properties of various Hgb
Hgb seen in sickle cell disease
Hgb S
Reagents used in sickle cell testing
- lysing agent
- dithionite solution (reducing agent)
Positive reaction in sickle cell testing
Precipitation/cloudy
More definitive tests for sickle cell testing
- Hgb electrophoresis
- HPLC
- Isoelectric focusing
Screening test for screening/monitoring various inflammatory states
Erythrocyte Sedimentation Rate (ESR)
Manual methods for determining ESR
Westergen
Wintrobe
2 principles used in cell counters
Impedance
Optical
Cell counter principle based on changes in electrical charge as cells (have low conductivity) move through an electrically conductive fluid to determine cell count
Impedance
The number of pulses in impedance counters corresponds to
Cell count
The pulse size in impedance counters correspond to
Cell size
Cell counter principle where it uses light scatter to determine the size and complexity of cells present as a single cell moves through a focused light source
Optical counts
Reagent used in Hgb measurement
Cyanmethemoglobin
Usual collection site for bone marrow samples
Posterior superior iliac crest
Bone marrow sample used to assess morphology and perform a diff count and M:E ratio
Aspirate
Normal range for M:E ratio
2:1 to 4:1
Bone marrow sample used to determine bone marrow cellularity
Core biopsy
An automated method of sorting cells
Flow cytometry
Factors that cause normal ranges to vary
- Age
- Gender
- Population
- Geographic distribution
Used in flow cytometry to determine cell size
Forward scatter
Used in flow cytometry to determine complexity of a cell
Side scatter
Electronic boundaries in flow cytometry to separate a specific population of interest
Gating
Flow cytometry; cell in suspension move through sheath fluid in a single-file line, allowing each to individually pass through a laser light
Hydrodynamic focusing
