Objective       To determine the cut-off points for supine and upright plasma levels of aldosterone (ALD) and for ratio of ALD/rennin (ARR) in primary aldosteronism (PA)

and investigate their diagnostic values to improve the diagnostic accura

cy of the disease.       Methods       Clinical data of 45 patients of pathologically confirmed PA and 50 age- and gender-matched patients of essential hypertension (EH) admitted in our hospital from 2006 to 2014 were collected in this study. Histological examination indicated that 34 PA patients were confirmed as adrenal adenoma and 11 as adrenal cortical hyperplasia. Serum potassium

and 24-hour urinary potassium

corticosteroid rhythm

catecholamine metabolites

and supine and upright plasma levels of rennin

angiotensinⅡ and ALD were measured. Moreover

the levels of ALD and ARR were analyzed to draw the receiver operating characteristic (ROC) curve and obtain the optimal cut-off points

and access the sensitivities and specificities of those indexes. Besides

the difference of ALD and ARR were compared between 2 kinds of pathological types of PA.       Results       There was no obvious difference in gender

age and blood pressure between PA and EH groups. Serum potassium and plasma renin activity were lower in PA than in EH group

but ALD ARR and 24-hour urinary potassium were higher. The optimal cut-off point of upright plasma ALD was 0.221 ng/mL

with a sensitivity of 0.561 and specificity of 0.909

that of supine plasma ALD was 0.175 ng/mL with a sensitivity of 0.829 and specificity of 0.795

that of upright ARR was 19.5 （ng·dL

-1

)/(ng·mL

-1

·h

-1

） with a sensitivity of 0.878 and specificity of 0.955

and that of supine ARR was 20.5 （ng·dL

-1

)/(ng·mL

-1

·h

-1

） with a sensitivity of 0.902 and specificity of 0.841. ARR was higher in patients with adrenal adenoma than those with adrenal cortex hyperplasia

especially the upright ARR.       Conclusion       The upright ALD and ARR have lower sensitivity than the supine ones

but higher specificity. So clinician should comprehensively consider the hormone test results on both supine and upright positions for hypertensive patients

moreover the results are associated with pathologic characteristics.