PTH was found useful to distinguish between patients with unilateral versus bilateral adrenal disease (PTH of 113.4 ± 45.7 ng/L versus 81.7 ± 29.9 pg/mL, p = 0.026) in one study; a value of PTH at 80 ng/mL was associated with a sensitivity and a specificity of 74% and 82%, respectively, to identify secondary hyperparathyroidism in PA [43]. The gene discussed is PTH; the disease is secondary hyperparathyroidism.