Aldosterone, a steroid hormone secreted by the adrenal cortex, is the principle mineralocorticoid controlling sodium and potassium balance. Serum aldosterone levels in normal upright adult individuals are generally less than 300 pg/ml. Only a fraction of urinary aldosterone is excreted intact, thus urinary excretion of aldosterone in normal adults is typically assessed as a combination of free aldosterone and aldosterone-18-glucuronide and is generally less than 20 µg/24 hr. Cayman's Aldosterone ELISA Kit is a competitive assay that can be used for quantification of aldosterone in serum, plasma, urine, and other sample matrices. The assay has a range from 15.6-2,000 pg/ml and a sensitivity (80% B/B0) of approximately 30 pg/ml.