The lucigenin assay can potentially give false-positive results, where quenching of the fluorescence of lucigenin is observed without transport taking place. Such results can be obtained either if the quantity of lucigenin outside the liposomes is large compared to encapsulated lucigenin or if the membranes of the liposomes have a lower integrity. Therefore, the quality of liposomes with encapsulated lucigenin must be verified in absence of transporters (blank experiments).