Determine when confirmatory testing can be bypassed for PA diagnosis
STEP 1 — Gather Information
Collect screening results: aldosterone-to-renin ratio (ARR) ≥200 (PAC/PRA) or ≥40 (PAC/ARC) with PAC ≥60 pg/mL (CLEIA); note spontaneous hypokalemia (serum K+ <3.5 mEq/L), baseline PAC >100 pg/mL (CLEIA), and renin suppression (PRA <0.5 ng/mL/h or ARC <2.5 pg/mL).
STEP 2 — Rule In / Rule Out
If the patient has a positive screening test AND exhibits spontaneous hypokalemia, baseline PAC >100 pg/mL (CLEIA), and renin suppression, rule in for bypassing confirmatory test; otherwise, rule out bypass and proceed to confirmatory testing.
STEP 3 — Classify or Stratify
Classify as eligible for confirmatory test bypass when all three criteria (spontaneous hypokalemia, high baseline PAC, renin suppression) are present; stratify as not eligible if any criterion is missing.
STEP 4 — Decide
Decide to skip confirmatory testing and move directly to subtype testing (e.g., adrenal venous sampling) for patients meeting all bypass criteria; for those not meeting criteria, order a confirmatory test (e.g., captopril challenge test or saline infusion test).
Clinical Guardrails / Mimics / Pitfalls
Do not bypass confirmatory testing in patients with borderline PAC (60–100 pg/mL CLEIA), normokalemia, or incomplete renin suppression; avoid mistaking diuretic-induced hypokalemia for spontaneous hypokalemia; remember that bypass does not exclude the need for subtype testing before adrenalectomy.
Concrete Clinical Example
A 45-year-old hypertensive patient presents with spontaneous hypokalemia (K+ 3.0 mEq/L), screening ARR 250 (PAC/PRA) with PAC 120 pg/mL (CLEIA), and PRA 0.2 ng/mL/h. All bypass criteria are met, so confirmatory testing is skipped and adrenal venous sampling is performed for subtype classification.
Source: Japan Endocrine Society clinical practice guideline for the diagnosis and management of primary aldosteronism 2021, Japan Endocrine Society, 2021