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HelpTest Code LAB2186 Aldosterone, 24 Hour, Urine
Additional Codes
ALDU
Useful For
Investigating primary aldosteronism (eg, adrenal adenoma/carcinoma and adrenal cortical hyperplasia) and secondary aldosteronism (renovascular disease, salt depletion, potassium loading, cardiac failure with ascites, pregnancy, Bartter syndrome) using 24-hour urine collections
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
UrineOrdering Guidance
Advice on stimulation or suppression tests is available from Mayo Clinic's Division of Endocrinology; call 800-533-1710.
Necessary Information
24-Hour volume (in milliliters) is required.
Specimen Required
Patient Preparation: Spironolactone (Aldactone) should be discontinued for 4 to 6 weeks before specimen collection. The plasma renin activity cannot be interpreted if the patient is being treated with spironolactone.
Supplies: Urine tubes, 10 mL (T068)
Container/Tube: Plastic, urine tube
Specimen Volume: 10 mL
Collection Instructions:
1. 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.
2. Collect urine for a full 24 hours (required) and record the total volume.
Additional Information: See Urine Preservatives-Collection and Transportation for 24-Hour Urine Specimens for multiple collections.
Specimen Minimum Volume
1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Urine | Refrigerated (preferred) | 28 days | |
| Frozen | 28 days | ||
| Ambient | 14 days |
Special Instructions
Reference Values
0-30 days: 0.7-11.0 mcg/24 h*
31 days-11 months: 0.7-22.0 mcg/24 h*
≥1 year: 2.0-20.0 mcg/24 h
*Loeuille GA, Racadot A, Vasseur P, Vandewalle B. Blood and urinary aldosterone levels in normal neonates, infants and children. Pediatrie. 1981;36(5):335-344
For International System of Units (SI) conversion for Reference Values, see www.mayocliniclabs.com/order-tests/si-unit-conversion.html
Day(s) Performed
Tuesday, Thursday
CPT Code Information
82088
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| ALDU | Aldosterone, U | 1765-7 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 8556 | Aldosterone, U | 1765-7 |
| TM47 | Collection Duration (h) | 13362-9 |
| VL45 | Volume (mL) | 3167-4 |
Interpretation
Urinary aldosterone excretion greater than 12 mcg/24 hours as part of an aldosterone suppression test is consistent with hyperaldosteronism.
For more information see Renin-Aldosterone Studies.
Method Description
Samples are spiked with deuterated internal standard and are hydrolyzed overnight with acid. Samples are then neutralized and extracted by solid phase extraction. The extracts are dried, reconstituted, and analyzed by liquid chromatography tandem mass spectrometry.(Taylor RL, Singh RJ. Validation of liquid chromatography-tandem mass spectrometry method for analysis of urinary conjugated metanephrine and normetanephrine for screening of pheochromocytoma. Clin Chem. 2002;48[3]:533-539; Wurth R, Tirosh A, Kamilaris CDC, et al. Volumetric modeling of adrenal gland size in primary bilateral macronodular adrenocortical hyperplasia. J Endocr Soc. 2020;5(1):bvaa162)
Report Available
2 to 8 daysSpecimen Retention Time
14 daysReject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.Method Name
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)