What ARR threshold and aldosterone level are commonly used to screen for primary hyperaldosteronism?

• A. Aldosterone >10 ng/dL with an ARR >10.
• B. Plasma aldosterone concentration typically >15 ng/dL with an ARR >20.
• C. Aldosterone >5 ng/dL with an ARR >5.
• D. Plasma aldosterone concentration >20 ng/dL with an ARR >50.

Answer: (B)

Screening for primary hyperaldosteronism relies on the fact that autonomous aldosterone secretion raises aldosterone while suppressing renin, so the aldosterone-renin ratio becomes markedly high. In practice, a commonly used threshold pairing is a plasma aldosterone concentration above about 15 ng/dL along with an ARR above about 20. This combination helps distinguish true autonomous aldosterone production from situations where renin is low for other reasons but aldosterone is not sufficiently elevated, or vice versa. If aldosterone is clearly elevated but the ARR is not, or if aldosterone is near the cutoff, the result is less definitive and may require repeat testing or additional evaluation.

The other thresholds tend to be less reliable: lowering the thresholds increases false positives, while requiring much higher values risks missing cases of PA. Remember that medications and clinical factors can affect renin and aldosterone levels, so these tests’re best interpreted in context and often followed by confirmatory testing if positive.