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HelpTest Code PALD Aldosterone, Plasma
Specimen Required
Collection Container/Tube: Lavender top (EDTA)
Submission Container/Tube: Plastic vial
Specimen Volume: 2 mL
Collection Instructions:
1. See Renin-Aldosterone Studies for detailed instructions.
2. The recommended collection time is 8 a.m., after the patient is active for approximately 2 hours. Try to collect the specimen as close to that time as possible and no later than 10 a.m.
3. Centrifuge and aliquot plasma into a plastic vial.
Useful For
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 syndrome) using plasma specimens
Testing Algorithm
For more information see Steroid Pathways.
Special Instructions
Method Name
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Reporting Name
Aldosterone, PSpecimen Type
Plasma EDTASpecimen Minimum Volume
1.2 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Plasma EDTA | Frozen (preferred) | 30 days | |
| Refrigerated | 28 days | ||
| Ambient | 4 days |
Reject Due To
| Gross hemolysis | OK |
| Gross lipemia | OK |
| Gross icterus | OK |
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 is not a major factor in regulating aldosterone secretion.
For more information see Steroid Pathways.
Reference Values
0-30 days: 17-154 ng/dL*
31 days-11 months: 6.5-86 ng/dL*
1-10 years:
≤40 ng/dL (supine)*
≤124 ng/dL (upright)*
≥11 years: ≤21 ng/dL (a.m. peripheral vein specimen)
*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.
Interpretation
A high ratio of plasma aldosterone (PA) in ng/dL to plasma renin activity (PRA) in ng/mL per hour, is a positive screening test result, a finding that warrants further testing. An PA/PRA ratio greater than or equal to 20 is only interpretable with an PA greater than or equal to 15 ng/dL and indicates probable primary aldosteronism.
Kidney disease, such as unilateral renal artery stenosis, results in elevated renin and aldosterone levels. Renal venous catheterization may be helpful. A positive test is a renal venous renin ratio (affected/normal) greater than 1.5.
Note: Advice on stimulation or suppression tests is available from Mayo Clinic's Division of Endocrinology and may be obtained by calling 800-533-1710.
Cautions
The plasma renin activity (PRA) cannot be interpreted if the patient is being treated with spironolactone (Aldactone). Spironolactone should be discontinued for 4 to 6 weeks before testing.
Late p.m. levels can be up to 30% lower than early a.m. levels. Supine values are on average 50% lower than upright collections. Sodium-deplete subjects have significantly elevated plasma aldosterone levels, potentially exceeding the upper limit of the salt replete upright reference range by several fold. To account for these variables, at least in part, it is recommended that PRA is measured concomitantly. In situations of physiological variability, PRA should be altered in the same direction as aldosterone. For more information see Renin-Aldosterone Studies.
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 PA/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.
Method Description
Aldosterone-d6 is added to serum and plasma samples as an internal standard. Aldosterone and aldosterone-d6 are extracted from the specimens using a Strata X cartridge. The eluate is dried down under nitrogen, reconstituted with 70/30 methanol/water containing estriol and analyzed by liquid chromatography tandem mass spectrometry using multiple reaction monitoring in the negative mode.(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. Anal Biochem. 1997;252(2):308-313)
Day(s) Performed
Monday through Friday
Report Available
2 to 5 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
82088
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| PALD | Aldosterone, P | 1763-2 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 65424 | Aldosterone, P | 1763-2 |