Aldosterone Levels Post-IV Saline Suppression Using Commercial Reference Laboratory Liquid Chromatography-Tandem Mass...

Area of Science:

• Endocrinology
• Clinical Chemistry
• Mass Spectrometry

Background:

• Diagnostic cutoffs for primary aldosteronism (PA) after intravenous (IV) saline suppression lack standardization.
• Current cutoffs rely on older immunoassays or research-based liquid chromatography tandem mass spectrometry (LC-MS/MS) assays.
• Aldosterone levels post-saline suppression using commercial LC-MS/MS assays are not well-characterized.

Purpose of the Study:

• To report aldosterone levels post-saline infusion using a commercial reference laboratory LC-MS/MS assay.
• To investigate diagnostic utility of commercial LC-MS/MS assays for PA detection.
• To establish potential diagnostic cutoffs for PA post-saline suppression.

Main Methods:

• Retrospective chart review of 35 patients undergoing saline suppression test.
• Aldosterone levels measured using a commercial reference laboratory LC-MS/MS assay.
• Patients classified as PA (n=26) or no PA (n=9) based on postsurgical outcomes and treatment response.

Main Results:

• Median baseline aldosterone higher in PA group (16.0 ng/dl) vs. no PA group (11.0 ng/dl), P=0.016.
• Post-saline infusion median aldosterone: 11.5 ng/dl (PA) vs. 1.0 ng/dl (no PA).
• In the no PA group, all patients had aldosterone levels ≤3.0 ng/dl post-saline suppression.

Conclusions:

• Commercial LC-MS/MS assays can detect low aldosterone levels post-saline suppression in confirmed PA.
• A post-saline suppression aldosterone level of 4.0 ng/dl may be a potential diagnostic marker for PA.
• Larger studies are needed to confirm these findings and establish definitive diagnostic cutoffs.