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Test ID: ALDNA Aldosterone with Sodium, 24 Hour, Urine

Reporting Name

Aldosterone with Sodium, Urine

Useful For

Investigation of 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

Clinical Information

Aldosterone stimulates sodium transport across cell membranes, particularly in the distal renal tubule where sodium is exchanged for hydrogen and potassium. Secondarily, aldosterone is important in the maintenance of blood pressure and blood volume.

 

Aldosterone is the major mineralocorticoid and is produced by the adrenal cortex. The renin-angiotensin system is the primary regulator of the synthesis and secretion of aldosterone. Likewise, increased concentrations of potassium in the plasma may directly stimulate adrenal production of the hormone. Under physiologic conditions, pituitary adrenocorticotropic hormone can stimulate aldosterone secretion.

 

Urinary aldosterone levels are inversely correlated with urinary sodium excretion. Normal individuals will show a suppression of urinary aldosterone with adequate sodium repletion.

 

Primary hyperaldosteronism, which may be caused by aldosterone-secreting adrenal adenoma/carcinomas or adrenal cortical hyperplasia, is characterized by hypertension accompanied by increased aldosterone levels, hypernatremia, and hypokalemia. Secondary hyperaldosteronism (eg, in response to renovascular disease, salt depletion, potassium loading, cardiac failure with ascites, pregnancy, Bartter's syndrome) is characterized by increased aldosterone levels and increased plasma rennin activity.

Interpretation

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.

 

See Renin-Aldosterone Studies in Special Instructions.

 

Note: Advice on stimulation or suppression tests is available from Mayo Clinic's Division of Endocrinology; call 800-533-1710.

Profile Information

Test ID Reporting Name Available Separately Always Performed
ALDU Aldosterone, U Yes Yes
NAU Sodium, U Yes Yes

Analytic Time

2 days

Day(s) and Time(s) Performed

Aldosterone: Monday, Thursday; 3 p.m.

Sodium: Monday through Sunday; Continuously

Clinical Reference

1. Young WF Jr: Primary aldosteronism: A common and curable form of hypertension. Cardiol Rev. 1999;7:207-214

2. Young WF Jr: Pheochromocytoma and primary aldosteronism: diagnostic approaches. Endocrinol Metab Clin North Am. 1977;26:801-827

3. Fredline VF, Taylor PJ, Dodds HM, Johnson AG: A reference method for the analysis of aldosterone in blood by high-performance liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry. AnalBiochem 1997 Oct 15;252(2):308-313

4. Carey RM, Padia SH: Primary mineralocorticoid excess disorders and hypertension. In: Jameson JL, De Groot LJ, de Kretser DM, Giudice LC, et al: eds. Endocrinology: Adult and Pediatric. 7th ed. WB Saunders; 2016:1871-1891

Method Name

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

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

Specimen Type

Urine


Specimen Required


Patient Preparation: If patient is taking spironolactone (Aldactone), it should be discontinued for 4 to 6 weeks before specimen collection.

Supplies: Aliquot Tube, 5 mL (T465)

Container/Tube: 2 Plastic, 5-mL tubes

Specimen Volume: 10 mL

Collection Instructions:

1. Collect urine for 24 hours.

2. Add 25 mL of 50% acetic acid as preservative at start of collection. Use 15 mL of 50% acetic acid for children under the age of 5 years. This preservative is intended to achieve a pH of between approximately 2 and 4.

3. Place 5 mL of well mixed, 24-hour urine in plastic, 5-mL tube and label as Aldosterone.

4. Place 5 mL of well mixed, 24-hour urine in plastic, 5-mL tube and label as Sodium.

Additional Information:

1. 24-Hour volume is required.

2. See Urine Preservatives-Collection and Transportation for 24-Hour Urine Specimens and Renin-Aldosterone Studies for more detailed instructions in Special Instructions.


Specimen Minimum Volume

Aldosterone: 1 mL/Sodium: 1 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Urine Refrigerated (preferred) 14 days
  Frozen  14 days
  Ambient  7 days

Reference Values

ALDOSTERONE

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

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

≥1 year: 2.0-20.0 mcg/24 hours

 

*Loeuille GA, Racadot A, Vasseur P, Vandewalle B: Blood and urinary aldosterone levels in normal neonates, infants and children. Pediatrie 1981;36:335-344

 

SODIUM

41-227 mmol/24 hours

If the 24-hour urinary sodium excretion is >200 mmol, the urinary aldosterone excretion should be <10 mcg.

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

82088-Aldosterone

84300-Sodium

LOINC Code Information

Test ID Test Order Name Order LOINC Value
ALDNA Aldosterone with Sodium, Urine 94871-1

 

Result ID Test Result Name Result LOINC Value
NA_24 Sodium, 24 Hr, U 2956-1
8556 Aldosterone, U 1765-7
TM47 Collection Duration 13362-9
TM11 Collection Duration 13362-9
VL9 Urine Volume 3167-4
VL45 Urine Volume 3167-4
NACN Sodium Concentration 21525-1

Urine Preservative Collection Options

Ambient

OK

Refrigerate

OK

Frozen

OK

50% Acetic Acid

Preferred

Boric Acid

OK

Diazolidinyl Urea

No

6M Hydrochloric Acid

No

6M Nitric Acid

No

Sodium Carbonate

No

Thymol

No

Toluene

No

 

Mayo Clinic Laboratories | Endocrinology Catalog Additional Information:

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