Section 15: Heme Instruments/troubleshooting Flashcards
(41 cards)
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
*Michelle: I think this is measured by oscilloscope. The Ohmmeter was her giving a simpler example of something else
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, nRBCs, big platelets
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:100 fl
Monos: 90-160fl
eos: 160 fl
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: variant lymphs
bottom left: imm neuts
bottom mid: eos
bottom right: blasts
How do you perform 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
