ARR cutoff values, depending on assay and based on whether PAC, PRA, and DRC are measured in conventional or SI units

ARR: aldosterone-renin ratio; DRC: direct renin concentration; PAC: plasma aldosterone concentration; PRA: plasma renin activity; SI: Systeme International.
* Values shown are on the basis of a conversion factor of PRA (ng/mL/hour) to DRC (mU/liter) of 8.2. DRC assays are still in evolution, and in a recently introduced and already commonly used automated DRC assay, the conversion factor is 12. It should be noted that there is poor correlation between DRC and PRA in the range where PRA is <1 ng/mL/h, the domain of major interest in primary aldosterone screening.
¶ The most commonly adopted cutoff values are shown in bold: 30 for PAC and PRA in conventional units (equivalent to 830 when PAC is in SI units) and 750 when PAC is expressed in SI units (equivalent to 27 in conventional units).