Patient selection: primary aldosteronism
Parameters in a patient without adrenal tumor on CT:
(1) serum potassium in mmol/L
(2) plasma aldosterone concentration in pg/mL
(3) aldosterone to renin ratio (ARR)
aldosterone to renin activity ratio =
= (aldosterone in pg/mL) / (renin activity in ng/mL per hour)
|
Parameter
|
Finding
|
Points
|
|
serum potassium
|
<= 3.4mmol/L
|
2
|
|
|
> 3.4 mmol/L
|
0
|
|
plasma aldosterone
|
< 165 pg/mL
|
0
|
|
|
>= 165 pg/mL
|
3
|
|
ARR
|
< 1000
|
0
|
|
|
>= 1000
|
3
|
total score =
= SUM(points for all 3 parameters)
Interpretation:
• minimum score: 0
• maximum score: 8
• The higher the score the greater the likelihood of unilateral disease.
• A score <= 3 probably has bilateral disease.
• A score >= 5 probably has unilateral disease.
|
Score
|
Sensitivity for Unilateral
|
Specificity for Unilateral
|
|
3
|
97%
|
59%
|
|
5
|
75%
|
95%
|
Performance:
• The area under the ROC curve is 0.92.
