Select the optimal confirmatory test for PA diagnosis

STEP 1 — Gather Information

Collect history of angioedema or ACEI use, baseline blood pressure control, renal function (eGFR), cardiac status (heart failure, arrhythmias), serum potassium, ability to perform urine collection, and patient preference for outpatient vs inpatient testing.

STEP 2 — Rule In / Rule Out

If the patient has no contraindications to captopril (no history of angioedema to ACEI, uncontrolled hypertension not a strict contraindication) and can undergo outpatient testing, rule in CCT as first-line; otherwise, rule out CCT and proceed to step 3.

STEP 3 — Classify or Stratify

Among remaining tests, stratify by contraindications:

• If uncontrolled hypertension, renal failure, heart failure, or profound hypokalemia → avoid SIT and FUT.
• If reliable 24‑h urine collection is possible and no severe renal impairment → consider OSLT.
• If urine collection unreliable or renal impairment present → consider FUT only if cardiac status permits; otherwise, individualized discussion.

STEP 4 — Decide

Choose CCT when feasible; otherwise select SIT if cardiac/renal status allows and hypokalemia correctable; choose OSLT when urine collection feasible and renal function adequate; choose FUT only when other tests are contraindicated and patient can tolerate upright posture with monitoring.

Clinical Guardrails / Mimics / Pitfalls

Do not use SIT or FUT in patients with uncontrolled hypertension, decompensated heart failure, or severe hypokalemia without correction; avoid OSLT in patients with unreliable urine collection or advanced renal failure due to false‑positives; never assume one test is superior based on diagnostic accuracy alone.

Concrete Clinical Example

A 62‑year‑old with hypertension, eGFR 38 mL/min/1.73 m², baseline K⁺ 3.2 mmol/L, and positive ARR screening. CCT is feasible (no angioedema history) and can be done outpatient despite CKD; SIT/FUT are relatively contraindicated due to renal impairment and hypokalemia; OSLT urine collection is challenging. Decision: perform CCT with close BP and K⁺ monitoring.

Source: Japan Endocrine Society clinical practice guideline for the diagnosis and management of primary aldosteronism 2021, Japan Endocrine Society, 2022