Chemistry
Adrenal related
Saline suppression test

Author: Renu Virk, M.D. (see Authors page)

Revised: 26 January 2016, last major update February 2010

Copyright: (c) 2002-2016, PathologyOutlines.com, Inc.

PubMed Search: Saline suppression [title]
Definition / General
Indication:

Methodology:
  • Infuse 2L of 0.9% saline over 4 hours ("saline infusion test") OR give oral NaCl tablets 10 - 12 gm daily for 3 days ("oral sodium loading test")
  • Blood levels: plasma aldosterone greater than 5 ng/dl (140 pmol/L) confirms the diagnosis of primary hyperaldosteronism
  • Urine levels: collect 24 hour urine for aldosterone, creatinine (to assess the adequacy of urine collection), and sodium (to ensure adequate intake) on the last day of sodium chloride administration
    • Aldosterone levels > 10 μg/24 hours (28 nmol/24 hours) confirms the diagnosis
Clinical Features
  • More difficult to perform than captopril suppression test, with comparable accuracy in patients with high sodium intake (Hypertension 2007;50:424)