Aldosterone with Sodium, 24 Hour, Urine

Alphabetical Test listing

Aldosterone with Sodium, 24 Hour, Urine-994

Test name:

Test number:

994

Excellian order number:

LAB994

Abbreviation:

MSO

Tests included:

ALDU
NAU

Useful for:

Investigating primary aldosteronism (eg, adrenal adenoma/carcinoma and adrenal cortical hyperplasia) and secondary aldosteronism (eg, renovascular disease, salt depletion, potassium loading, cardiac failure with ascites, pregnancy, Bartter syndrome) in conjunction with urine sodium levels

Patient preparation information:

Spironolactone (Aldactone) should be discontinued for 4 to 6 weeks before testing. The plasma renin activity cannot be interpreted if the patient is being treated with spironolactone.

Specimen type:

Urine, 24-hr

Collection container:

Urine collection container with 30mL 30% acetic acid - 24 hr

Volume:

10 mL

Minimum volume:

2 mL

Collection instructions:

Container MUST be labeled with patient's full name, date and time collection started, and date and time collection finished.

How to collect a 24-hr urine sample

Processing instructions:

Measure and record the total volume of 24-hour collection
Mix sample well
Transfer 5 mL of sample into Screw cap transfer vial/tube (Mayo T914) labeled as Aldosterone
Transfer 5 mL of sample into Screw cap transfer vial/tube (Mayo T914) labeled as Sodium

Transport container:

Screw cap transfer vial/tube (Mayo T914)

x 2

Alternate collection container:

Urine collection container with 10g boric acid - 24 hr

Alternate collection instructions:

Container MUST be labeled with patient's full name, date and time collection started, and date and time collection finished.

How to collect a 24-hr urine sample

Alternate processing instructions:

Measure and record the total volume of 24-hour collection
Mix sample well
Transfer 5 mL of sample into Screw cap transfer vial/tube (Mayo T914) labeled as Aldosterone
Transfer 5 mL of sample into Screw cap transfer vial/tube (Mayo T914) labeled as Sodium

Alternate transport container:

Screw cap transfer vial/tube (Mayo T914)

x 2

Required forms/information:

24-Hour volume is required.

Transport and stability:

Refrigerated (preferred) - 14 days

Ambient - 7 days

Frozen - 14 days

Performing lab:

Mayo Clinic Laboratories (ALDNA): R-NX

Days set up:

Tu, Th

TAT:

2 - 8 days

Method:

ALDU: Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)

NAU: Potentiometric, Indirect Ion-Selective Electrode (ISE)

Reference ranges:

ALDOSTERONE

0-30 days: 0.7-11.0 mcg/24 h*

1-11 months: 0.7-22.0 mcg/24 h*

> or =1 year: 2.0-20.0 mcg/24 h

SODIUM

41-227 mmol/24 h

If the 24-hour urinary sodium excretion is greater than200 mmol, the urinary aldosterone excretion should be less than10 mcg.

Clinical information:

Under normal circumstances, if the 24-hour urinary sodium excretion is greater than 200 mEq, the urinary aldosterone excretion should be less than 10 mcg/24 hours.

Urinary aldosterone excretion greater than 12 mcg/24 hours as part of an aldosterone suppression test is consistent with hyperaldosteronism.

Twenty-four-hour urinary sodium excretion should exceed 200 mEq to document adequate sodium repletion.

Cautions:

Angiotensin converting enzyme (ACE) inhibitors have the potential to "falsely elevate" PRA. Therefore, in a patient treated with an ACE-inhibitor, the findings of a detectable PRA level or a low sodium aldosterone/PRA ratio do not exclude the diagnosis of primary aldosteronism. In addition, a strong predictor for primary aldosteronism is a PRA level undetectably low in a patient taking an ACE-inhibitor.

CPT codes:

82088-Aldosterone
84300-Sodium

Date created:

06/08/2023

Revised date:

08/22/2023