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Epic Test Code LAB557 Aldosterone, Serum

Additional Codes

MML Code: ALDS

 

NY State Approved

Yes

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Reporting Name

Aldosterone, S

Method Name

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

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 28 days
  Frozen  30 days
  Ambient  4 days


Specimen Required


Patient Preparation: 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.

Collection Container/Tube:

Preferred: Red top

Acceptable: Serum gel

Submission Container/Tube: Plastic vial

Specimen Volume: 1.2 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 serum into a plastic vial.


Bassett Healthcare Network Clinical Laboratories Note:

Blood Tube Draw Volume
Min 50% draw volume  

Specimen Type

Serum

Specimen Minimum Volume

1.2 mL

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 Jul-Aug;36(5):335-344

 

For International System of Units (SI) conversion for Reference Values, see www.mayocliniclabs.com/order-tests/si-unit-conversion.html

Report Available

2 to 5 days

Day(s) Performed

Monday through Friday

CPT Code Information

82088

Reject Due To

Gross hemolysis OK
Gross lipemia OK
Gross icterus OK

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)

Testing Algorithm

For more information see Steroid Pathways

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

Interpretation

A high ratio of serum aldosterone (SA) 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 SA/PRA ratio greater than or equal to 20 is only interpretable with an SA 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; call 800-533-1710.

Cautions

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 patients have significantly elevated serum aldosterone (SA) 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 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.

Specimen Retention Time

14 days

Forms

If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:

-General Request (T239)

-Cardiovascular Test Request (T724)