Study on the Diagnostic Cut-off Point of 24-hour Urinary Aldosterone Measured by Liquid Chromatography-Tandem Mass Spectrometry in the Diagnosis of Primary Aldosteronism in the Oral Sodium Loading Test

Primary aldosteronism (PA) is the most common cause of secondary hypertension. Liquid chromatography - tandem mass spectrometry (LC-MS/MS) is more accurate than the traditional radioimmunoassay in measuring aldosterone. This study aims to establish a more precise diagnostic threshold for the oral sodium loading test (OSLT) by using LC-MS/MS to measure urinary aldosterone levels. We will combine the biochemical results of OSLT and other data from healthy volunteers and suspected PA patients to determine a new 24-hour urinary aldosterone threshold. We expect to improve the diagnostic accuracy of PA, helping clinicians identify this curable cause of hypertension earlier and more accurately, and achieving precise treatment.

Study Overview

• Status: Recruiting
• Conditions: Primary Aldosteronism
• Intervention / Treatment: Diagnostic test: The oral sodium loading test

• Study Type: Observational
• Enrollment (Estimated): 800

Contacts and Locations

• Study Contact: Name: Tong Anli; Phone Number: +8613460884085; Email: tonganli@hotmail.com

Study Locations

• China
  • Beijing Municipality
    • Beijing, Beijing Municipality, China, 100000
      • Recruiting
      • Peking Union Medical Colledge Hospital
      • Contact: Li Zewen; Email: b2023001041@pumc.edu.cn

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

1）Healthy Controls to establish physiological suppression limits.2) Patients with suspected PA undergo oral sodium loading test to determine the cut-off point.

Description

Inclusion criteria for the normal control group: Age 18-70 years old, BMI: 18.5-23.9kg/m ²，gender not restricted. blood pressure: 100-120/60-80mmHg. no history of hypertension. No abnormal nodules found in adrenal CT. Previous blood potassium and electrocardiogram were all within normal ranges., No history of liver or kidney dysfunction, malignant tumors, metabolic diseases or cardiovascular diseases, and no medication used.

Exclusion criteria: Those with a family history of hypertension or with clinical manifestations of secondary hypertension. Those who have been taking drugs that may affect the RAAS system for a long time (such as contraceptives, steroids, etc.). Those with cardiac dysfunction or severe arrhythmia and unable to tolerate the test.

Patients with suspected primary aldosteronism in the outpatient setting. Inclusion criteria: Patients with suspected primary aldosteronism in the outpatient setting. Willing to undergo 4-week spironolactone treatment and cooperate with follow-up.

Exclusion criteria: Patients who did not complete the oral sodium loading test. Patients with Cushing's syndrome or other endocrine tumors. Patients allergic to spironolactone or with contraindications for its use (such as severe hyperkalemia, eGFR < 30).History of liver or kidney dysfunction, coexisting severe cardiovascular or cerebrovascular diseases, history of malignant tumors, other types of endocrine hypertension (hyperthyroidism, pheochromocytoma, Cushing's syndrome, etc.), renal artery stenosis, hypokalemia caused by other factors (renal tubular acidosis, Bartter syndrome, Gitelman syndrome, etc.), diabetes with HbA1c > 7.0% or currently using or having used insulin or SGLT2 inhibitor drugs, taking special medications such as glucocorticoids, immunosuppressants, oral contraceptives, etc.

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
normal sujects; Healthy volunteers with normal blood pressure and blood potassium levels and no adrenal nodules. These volunteers were used to determine the normal physiological range (lower limit value) of aldosterone inhibition after the test.	Diagnostic test: The oral sodium loading test; These subjects underwent a three-day high-salt diet test, during which they consumed an additional 6-10 grams of salt each day. On the third day, tests were conducted on the aldosterone, sodium, potassium and creatinine levels in the 24-hour urine, blood potassium, creatinine, standing aldosterone concentration, plasma renin activity, and the steroid hormone profile.
Patients suspected of having primary aldosteronism	Diagnostic test: The oral sodium loading test; These subjects underwent a three-day high-salt diet test, during which they consumed an additional 6-10 grams of salt each day. On the third day, tests were conducted on the aldosterone, sodium, potassium and creatinine levels in the 24-hour urine, blood potassium, creatinine, standing aldosterone concentration, plasma renin activity, and the steroid hormone profile.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
24-hour urinary aldosterone levels after a 3-day high-sodium diet	Two weeks after completing the oral sodium loading test

Collaborators and Investigators

• Sponsor: Peking Union Medical College Hospital

Study record dates

Study Major Dates

• Study Start (Actual): April 1, 2025
• Primary Completion (Estimated): July 1, 2026
• Study Completion (Estimated): August 1, 2026

Study Registration Dates

• First Submitted: June 3, 2026
• First Submitted That Met QC Criteria: June 3, 2026
• First Posted (Actual): June 9, 2026

Study Record Updates

• Last Update Posted (Actual): June 9, 2026
• Last Update Submitted That Met QC Criteria: June 3, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: diagnose; the oral sodium loading test
• Additional Relevant MeSH Terms: Endocrine System Diseases; Pathologic Processes; Adrenal Gland Diseases; Adrenocortical Hyperfunction; Pathological Conditions, Signs and Symptoms; Disease; Hyperaldosteronism
• Other Study ID Numbers: pumch-06086-10

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No