Patent ID: 7198953

Claim:
A method of using a reference control composition for measurement of nucleated red blood cells comprising the steps of: (a) providing a reference control composition to a flow cytometric instrument, said reference control composition comprising a nucleated red blood cell component made of stabilized animal nucleated red blood cells; wherein said stabilized animal nucleated red blood cells have impedance properties simulating impedance properties of human nucleated red blood cells under a blood lysing condition as measured by an impedance measurement; (b) mixing said reference control composition with a lytic reagent to form a control sample mixture; wherein upon exposing to said lytic reagent said stabilized animal nucleated red blood cells are substantially lysed and cellular volume thereof reduce to substantially nuclear volume; (c) measuring said control sample mixture by said impedance measurement to measure said substantially lysed animal nucleated red blood cells from step (b); (d) performing an analysis of signals obtained from said impedance measurement in step (c) and obtaining numbers of simulated human nucleated red blood cells from said analysis; and (e) reporting said numbers of simulated human nucleated red blood cells in said reference control composition.