Test Indications: Investigating primary aldosteronism (eg, adrenal adenoma/carcinoma and adrenal cortical hyperplasia) and secondary aldosteronism (eg, renovascular disease, salt depletion, potassium loading, cardiac failure with ascites, pregnancy, Bartter syndrome).

See Hypertension Canada’s 2020 Guidelines for more information.

Patient preparation instructions: Unrestricted sodium intake.

As per physician’s instructions:

·        Withdraw interfering agents/medications

·        Discontinue oral contraceptives or hormone replacement therapy (estrogen leads to false positive ARR). Alternative is to measure renin activity, consult Clinical Biochemist for details.

See F10-50-45D Approved Physicians for Specialist Endocrinology Requisition

Method of Analysis: DiaSorin Chemiluminescence for aldosterone and renin

Renal impairment

- Decrease in renin activity, thus increasing ARR and contribute to a false positive result

Age

-  Renin and aldosterone decrease with age (renin more so than aldosterone), resulting in higher ARR

Sex        

- Renin is lower in females than males

- Aldosterone is similar between sexes during follicular phase of menstrual cycle in females, but higher in females during luteal phase

- Thus, ARR is higher in females for all menstrual cycle phases, but especially the luteal phase

- Thus, blood should be collected during follicular phase in females to reduce the risk of a false positive Pregnancy

- Aldosterone and renin are increased, resulting in lower ARR and increased possibility of a false negative

Oral contraceptives

- Lower renin mass, but not activity, leading to higher ARR if renal mass is measured