Aldosterone-to-renin ratio (ARR) is the mass concentration of aldosterone divided by the plasma renin activity in blood plasma. The aldosterone/renin ratio is recommended as screening tool for primary hyperaldosteronism.
Aldosterone-to-renin ratio can be given in ng/dL per ng/(mL·h), that is, nanogram per decilitre of aldosterone per nanogram per (millilitre x hour) of renin. Also, it can be given in pmol/liter per µg/(liter·h), where aldosterone is given in molar concentration. The former can be converted to the latter by multiplying with 27.6. Also, the inverse value is occasionally given, that is, the renin-to-aldosterone ratio, whose value is the multiplicative inverse of the aldosterone-to-renin ratio.
The cutoff normal individuals from those with primary hyperaldosteronism is significantly affected by the conditions of testing, such as posture and time of day. On average, an ARR cutoff of 23.6 ng/dL per ng/(mL·h), expressed in alternative units as 650 pmol/liter per µg/(liter·h), has been estimated to have a sensitivity of 97% and specificity of 94%. An ARR value in an individual that is higher than the cutoff indicates primary hyperaldosteronism.
If the inverse ratio (i.e. renin-to-aldosterone) ratio is used, a value lower than the cutoff indicates primary hyperaldosteronism.
|Aldosterone-to-renin ratio||Renin-to-aldosterone ratio|
|13.1, 23.6, 35.0||ng/dl per ng/(ml·h)||0.029, 0.042, 0.076||ng/(ml·h) per ng/dl|
|360, 650, 960||pmol/liter per µg/(liter·h)||0.0010, 0.0015, 0.0028||µg/(liter·h) per pmol/liter|
- Tiu, S. -C.; Choi, C. -H.; Shek, C. -C.; Ng, Y. -W.; Chan, F. K. W.; Ng, C. -M.; Kong, A. P. S. (2004). "The Use of Aldosterone-Renin Ratio as a Diagnostic Test for Primary Hyperaldosteronism and Its Test Characteristics under Different Conditions of Blood Sampling". Journal of Clinical Endocrinology & Metabolism. 90: 72–78. PMID 15483077. doi:10.1210/jc.2004-1149. 
- Converted from mass concentration value by multiplying with 27.6
- Aldosterone-Renin Ratio in Primary Hyperaldosteronism by Allan S. Brett. Posted: 03/15/2005; Journal Watch. 2005;4(2)
- Multiplicative inverse of corresponding aldosterone-to-renin ratio