Saline Suppression Test (Investigation Guide)
A saline suppression test helps confirm the diagnosis of Conn's syndrome (primary hyperaldosteronism) by checking whether aldosterone levels suppress normally after a salt water infusion.
Why it's done
- used as a confirmatory test after an initial screening blood test suggests excess aldosterone
- confirms the diagnosis before further imaging or treatment
- guides the right next steps
What we offer
- some blood pressure medications adjusted beforehand under guidance if needed
- a saline infusion given while lying down, followed by a blood test
- results explained clearly, with further imaging arranged if the diagnosis is confirmed
What the test assesses
Saline suppression testing evaluates whether aldosterone falls appropriately after a controlled intravenous saline infusion and can help confirm primary aldosteronism following an abnormal screening result. Aldosterone is interpreted with renin, potassium and the clinical context.
Preparation and safety
The testing team will advise about potassium correction, salt intake and medicines that affect aldosterone or renin. Blood pressure and clinical status are monitored during the infusion. The test may be unsuitable in significant heart failure, uncontrolled hypertension or advanced kidney disease, so individual safety assessment is essential.
Results and UK-wide review
Results guide whether adrenal imaging and sometimes adrenal vein sampling are appropriate. Findings can usually be reviewed securely by video, while the infusion must take place in a supervised local facility.