full blood count Flashcards
packed cell volume
haemoatocrit
(PCV) is a measurement of the proportion of blood that is made up of cells. The value is expressed as a percentage or fraction of cells in blood.
benefits of autmation
capacity cost time precison accuracy
two methods of automation of cell counting
aperture imedance
optical
what is aperture imedance counter
particel cell counter
cells in isoltonic solution
-cells pass through aperture and displaces volume affecting electrical current in system
what info does impendance aperture giev
mangitue of pulses equates of volume of cells
number of impedance chanes equates to concetration of particles
problems with basic aperture impedance counting
shear force near aperture can deform cells
sizing is infeucned by orientation of cells
cannot count mixed populations of cells
what is sheath stream focussing
stream of separate cells focussed on a counting zone to better size and count cells in a mxed pop
how can you differentiation WBC
on their size on the grah read out
granulocytes are largest
what is differential lyis
technique to selectively lyse different populations of WBC to be then used in aperture impedance and optical counting
optical cell counting
number of pulses through the system proportional to cell count
narrow forward scatter i cell vol
wide angel scatter is refractive index
ESR
erythrocyte sedimentation rate
accessory test fir FBC
non specific test now automated
use of ESR
RBC form roulaeux and sedement
can be used to detect soe conditions such as acute phase reactants
ESR ormal range
0-20mm in 1 hr
degree of sedementation infleunced by:
- inflamation, sepsis, malignancy,immungolbuil levels
