Section 15: Heme Instruments/troubleshooting COPY Flashcards
What methods does the Coulter Principle use?
Impedance or direct current technology
What does the Coulter Principle do in terms of cells?
basic principle of counting and sizing particles in two containers separated by a small hole (aperture) and electrodes are on top of each container
In the coulter principle, how is resistance measured? What solution is added?
with electrodes connected to a ohmmeter, a saline solution is added
In the coulter principle, after cells are added to one side and the spigot is opened what happens?
each time a cell passes through the aperture it displaces a small amount of electrolyte and increases resistance between electrodes
If you drain 1mL from the cell side of the container (coulter principle) and count the number of needle flicks, what would you learn?
you would learn the number of cells per mL in suspension
What happens if you replace the ohmmeter with a battery oscilloscope in the coulter principle?
each cell through the aperture creates an electrical pulse/spike on the oscilloscope and the height of the spike is proportional to cell sizes
What is a threshold?
a set size limit used to choose a pulse size
what is a channel?
area between thresholds, can be used to sort a population into many subgroups by size
what are some notes about the aperture impedance system?
eliminates recirculation of cells
cells pushed away from critical (counting) zone by diluent
more accurate counts
what is coincidence correction?
provides accurate histograms and reliable cell sizing for RBC and PLT indices
what kind of counting does the aperture impedance system use?
triplicate counting, ensures precision and reduces repeats
Describe the RBC histogram pictured
normal :)
Describe the RBC histogram(s) pictured
top left: cold aggultination
top right: macrocytosis, target cells..etc
bottom left: rbc fragments, microcytes
bottom right: DI rbcs, transfusion (dimorphic)
What things are measured with RBC grading?
accurate MCV, RDW
detects DI populations
Micro rbc/fragments
agglutination
Describe the PLT histogram
normal
What does PLT curve fitting do?
allows more accurate counts when PLT are larger than 20 fL
PLT counting and sizing: coulter impedance counting has what kind of curve fitting? what does it do?
has patented curve fitting and is a process that is used in conjugation w/ wbc histogram review for plt clumps and giant plt flags
Describe what is happening in the plt histograms
top: giant plts
bottom: small plts
Coulter wbc histogram: what cells correspond to the REL NO.?
Lymphs: 50-90fl
baso
Monos: 90-160fl
eos
Neuts: 160-450fl
How many fL are lymphs, Monos and Neuts each?
Lymphs - 50-90fl
Monos - 90 - 160 fl
Neuts - 160 - 450fl
Describe the WBC histograms present
top left: granulocytes w varied sizes, immature neuts
top mid: lymphocytosis
top right: varient lymphs/blasts
bottom left: imm neuts
bottom mid: eos
bottom right: varient lymphs/blasts
Near native wbc analysis
rbc removed from dilution using lytic process; second agent prevents alteration of white cells
notes about hydrodynamically focused flowcell
laminar flow ensures single file cell passage
coincidence effects are minimal
What is flow cytometry?
technique for counting/exam/sorting particles suspended in a fluid stream. Allows multiparametric analysis of characteristics of single cells
What are some factors of biophysical flow cytometry?
cells are hydrodynamically focused, diluted blood is injected into “sheath” of buffered saline which forces cellls past detector
VCS technology uses what three main principles?
volume, light scatter and conductivity
What are some main principles used by the 3-D VCS Scatterplot?
nuc shape and comp
granules
cytoplasm
cell size
Define the following terms in regards to coulter VCS technology:
Volume
Conductivity
light scatter:
volume = size
conductivity = internal comp
light scatter = cell shape/surface
how is total cell volume measured?
measured using reference method of direct current impedance and is unaffected by cell orientation
Conductivity: how is internal cell structures measured?
measured via radiographic imaging (similar to ultrasound)
proprietary technology
how is light scatter/cell surface granularity measured?
measured using a broad range of angles. over 60 angles of light scatter are analyzed
3-D cellular analysis - VCS measures what three things in the 3D field?
Volume, conductivity, light scatter are all directly measured
Describe the data plot
normal
Sysmex direct current w/ hydrodynamic focus uses what and measures what?
uses fluorescent flow cytometry - nuc acid and cytoplasmic organelles
measures fluorescnes and side angle light scatters
Sysmex WBC measures what?
measures the forwards scatter, side scatter and side fluorescenes of wbc populations
sysmex WBC placement in the scatter is based on what two components?
size (forwards scatter) and internal comp (side)
sysmex RBC counting method: RBC and HCT are measured based on what technology?
impedence technology (DC) HCT measured based on volume of rbc determined by DC detection
sysmex hemoglobin measurement is used with?
utilizing Sodium Lauryl Sulfate (SLS) has no cyanide and minimal interface in lipemic samples or w ab proteins
What are the three steps in SLS measurement?
1.) denaturation of globin molecule
2.) oxidation of heme molecule
3.) conversion of SLS-hgb
Siemens healthcare: Advia: what are the three main points?
flow cytometry based
light scatter
MPO
Abbott Cell-DYN sapphire: what are the 4 main focusing points?
optical light scatter
fluorescence
impedance
MAPSS
