REN and urokinase-type plasminogen activator measurement: Univariate logistic regression analysis showed that nadir serum potassium value, supine PAC, PAC at time 4 h of SIT, and positive adrenal imaging results (unilateral nodule) were significantly associated with a diagnosis of UPA, while other parameters such as age, sex, PAC measured in a sitting position, or aldosterone-to-renin ratio were not (Table 2).