Three functional hERG channel assay methods have been developed and evaluated. The methods were tested against five known hERG channel inhibitors: dofetilide, terfenadine (Seldane), sertindole (Serdolect), astemizole (Hismanal), and cisapride (Propulsid). The DiBAC4(3)-based assays were found to be the most economical but had high false-hit rates as a result of the interaction of dye with the test compounds. The membrane potential dye assay had fewer color-quenching problems but was expensive and still gave false hits. The nonradioactive Rb+ efflux assay was the most sensitive of all the assays evaluated and had the lowest false-hit rate.
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