Flow cytometric analysis of granulocytes using FLAER. (A) As a control setting, there was no evidence of decreased (type II PNH cells) or absent (type III PNH cells) expression of FLAER. (B) In this patient, decreased (42.4%) and absent (57.0%) FLAER fractions were detected, suggesting that 99.4% of PNH granulocyte clones had a FLAER deficiency, which is consistent with classic PNH.

Abbreviations: FITC, fluorescein isothiocyanate; FLAER, fluoresceinlabeled proaerolysin; PNH, paroxysmal nocturnal hemoglobinuria.