THIS ASSAY IS PREFERRED AS A SCREENING TEST FOR CUSHING SYNDROME. IT ALSO HELPS IN THE DIAGNOSIS OF PSEUDO-HYPERALDOSTERONISM DUE TO EXCESSIVE LICORICE CONSUMPTION. THE TEST HAS LIMITED USEFULNESS IN THE EVALUATION OF ADRENAL INSUFFICIENCY.

ALDOSTERONE LEVELS ARE MEASURED TO HELP DIAGNOSE CONDITIONS THAT CAUSE HIGH OR LOW BLOOD PRESSURE. ELEVATED LEVELS CAN INDICATE PRIMARY ALDOSTERONISM (CONNS SYNDROME), A CONDITION WHERE THE ADRENAL GLANDS PRODUCE TOO MUCH ALDOSTERONE. LOW LEVELS CAN BE A SIGN OF ADDISONS DISEASE.

DEOXYCORTICOSTERONE (DOC) IS A PRECURSOR OF CORTICOSTERONE AND ALDOSTERONE. HIGH LEVELS ARE OBSERVED IN PATIENTS WITH 11-HYDROXYLASE DEFICIENCY. PATIENTS WITH DOC SECRETING TUMORS ALSO EXHIBIT HYPERTENSION.

MEASUREMENT OF CORTICOSTERONE IS USED AS AN ADJUNCT TO 11-DEOXYCORTICOSTERONE AND 11-DEOXYCORTISOL MEASUREMENT IN THE DIAGNOSIS OF CYP11B1 AND CYP11B2 DEFICIENCIES, RARE GLUCOCORTICOID RESPONSIVE HYPERALDOSTERONISM AND ISOLATED LOSS OF FUNCTION OF 18 HYDROXYLASE AND 18 METHYLOXIDASE ACTIVITY OF CYP11B2. IT ALSO HELPS TO EVALUATE CONGENITAL ADRENAL HYPERPLASIA IN NEWBORNS WHERE ELEVATION OF 17 HYDROXYPROGESTERONE IS ONLY MODERATE.

MEASUREMENT OF BOTH FREE CORTISOL AND CORTISONE ARE USEFUL IN DIAGNOSING PATIENTS WITH LOW-RENIN HYPERTENSION CAUSED BY APPARENT MINERALOCORTICOID EXCESS. THIS MAY BE DUE TO EITHER AN INHERITED DEFECT IN 11HSDB2 ENZYME OR AN ACQUIRED INHIBITOR OF THE ENZYME BY SUCH COMPOUNDS AS GLYCYRRHIZIC ACID, A COMPONENT OF NATURAL LICORICE.