[Establishing LC-MS/MS-based cutoffs for the confirmatory testing for primary aldosteronism: a prospective...

Area of Science:

• Endocrinology
• Clinical Diagnostics
• Mass Spectrometry

Background:

• Primary aldosteronism (PA) is a common cause of secondary hypertension.
• Accurate diagnosis of PA is crucial for appropriate management and preventing cardiovascular complications.
• Confirmatory tests like the captopril challenge test (CTT) and seated saline infusion test (SIT) are used, but their diagnostic utility requires further evaluation.

Purpose of the Study:

• To assess the diagnostic performance of the CTT and SIT for primary aldosteronism (PA) using liquid chromatography-tandem mass spectrometry (LC-MS/MS).
• To establish optimized diagnostic cutoffs for plasma aldosterone concentration (PAC) and aldosterone-to-renin ratio (ARR) in these confirmatory tests.

Main Methods:

• A prospective multicenter diagnostic trial involving patients at high risk for PA.
• Participants underwent screening with aldosterone-to-renin ratio (ARR) followed by CTT and seated SIT.
• Plasma aldosterone concentrations (PACs) and renin levels were measured using LC-MS/MS, with PA diagnosis based on specific criteria.

Main Results:

• Both CTT and SIT demonstrated excellent diagnostic performance with high area under the receiver operating characteristic curve (AUC) values for ARR and PAC using LC-MS/MS.
• Optimized cutoffs were identified: for CTT, PAC ≥5.7 ng/dl or ARR ≥9.3; for seated SIT, PAC ≥5.0 ng/dl or ARR ≥19.0.
• LC-MS/MS-based ARR and PAC measurements showed superior diagnostic efficacy compared to plasma renin activity (PRA).

Conclusions:

• The CTT and SIT, when analyzed with LC-MS/MS, are highly effective confirmatory tests for primary aldosteronism.
• The study provides optimized diagnostic cutoffs for PAC and ARR for both CTT and SIT, aiding in accurate PA diagnosis.
• These findings support the use of LC-MS/MS in conjunction with CTT and SIT for improved primary aldosteronism diagnosis.