Aldosterone with Sodium, Urine
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Investigation of 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's syndrome)
Profile Information A profile is a group of laboratory tests that are ordered and performed together under a single Mayo Test ID. Profile information lists the test performed, inclusive of the test fee, when a profile is ordered and includes reporting names and individual availability.
|Test ID||Reporting Name||Available Separately||Always Performed|
Special Instructions and Forms Describes specimen collection and preparation information, test algorithms, and other information pertinent to test. Also includes pertinent information and consent forms to be used when requesting a particular test
ALDU/8556: Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
NAU/8525: Potentiometric, Indirect Ion-Selective Electrode (ISE)
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Aldosterone with Sodium, Urine
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Collection Container/Tube: Plastic, 60-mL urine bottle
Submission Container/Tube: Plastic, 10-mL urine tube (Supply T068) and plastic, 6-mL tube (Supply T465)
Specimen Volume: 16 mL
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 <5 years old. This preservative is intended to achieve a pH of between approximately 2 and 4.
3. Place 11 mL of well mixed, 24-hour urine in plastic, 10-mL urine tube (Supply T068) and label as Aldosterone.
4. Place 5 mL of well mixed, 24-hour urine in plastic, 6-mL tube (Supply T465) and label as Sodium.
1. 24-Hour volume is required.
2. See Urine Preservatives for multiple collections and Renin-Aldosterone Studies for more detailed instructions in Special Instructions.
Urine Preservative Collection Options
50% Acetic Acid
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Aldosterone: 6 mL/Sodium: 0.25 mL
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
|Urine||Refrigerated (preferred)||7 days|
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
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 subjects 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.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
0-30 days: 0.7-11.0 mcg/24 hours*
1-11 months: 0.7-22.0 mcg/24 hours*
> or =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
41-227 mmol/24 hours
If the 24-hour urinary sodium excretion is >200 mmol, the urinary aldosterone excretion should be <10 mcg.
Under normal circumstances, if the 24-hour urinary sodium excretion is >200 mEq, the urinary aldosterone excretion should be <10 mcg/24 hours.
Urinary aldosterone excretion >12 mcg/24 hours as part of an aldosterone suppression test is consistent with hyperaldosteronism.
24-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 and may be obtained by calling Mayo Medical Laboratories.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
The plasma renin activity (PRA) cannot be interpreted if the patient is being treated with spironolactone (Aldactone). Spironolactone (Aldactone) should be discontinued for 4 to 6 weeks before testing.
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 (SA)/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.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
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
Method Description Describes how the test is performed and provides a method-specific reference
Sodium is performed by flame emission spectrometry/indirect ion-selective electrode (ISE).
Aldosterone is performed by liquid chromatography-tandem mass spectrometry (LC-MS/MS).
Samples are spiked with deuterated internal standard and are hydrolyzed overnight with acid. Samples are then neutralized and extracted by solid phase extraction (SPE). The extracts are dried, reconstituted, and analyzed by LC-MS/MS. (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 Mar; 48:533-539)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Aldosterone: Monday, Thursday; 3 p.m.
Sodium: Monday through Sunday; Continuously
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
See Individual Unit Codes
Performing Laboratory Location The location of the laboratory that performs the test
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
|Result ID||Reporting Name||LOINC Code|
|NA_24||Sodium, 24 Hr, U||2956-1|