lecture 16 manual cell counting Flashcards Preview

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Flashcards in lecture 16 manual cell counting Deck (9):

advantages of automated vs manual cell counting

high specimen through put, multi test instruments, smaller volumes, direct to LIS, more accurate/precise


how electrical impedance is used to count cells and determine size

aperture set to allow certain size to pass. increases resistance as cells pass equals a pulse


how light scatter can differentiate WBC

different cell structures refract, diffract or reflect light at diff angles


in what situations is manual count performed

count below detection limit of insurgent, on CSF and synovial fluid, remote 3rd world countries


magnification and microscope set up for manual WBC and platelet count

10x objective for WBC. 40x objective for platelets


standard dilutions and diluent for WBC, platelet, RBC counts

dimension and volume of WBC counting square


what to do if 2 counts differ by more than 15 cells

repeat chamber loading and counting procedure


6 errors that affect accuracy/precision of manual count

inadequate specimen/dilution mixing, improper dilution, under fill chamber, leaving WBC in lysing diluent too long, humidified chamber drying out, not using hemocytometer slip, improper counting, uneven distribution of cells


formula for cell count

(avg cell count/0.4 uL total volume) * 20 DF * 10^6 ul/L vol correction factor