Aldosterone, 24-Hour Urine

Casandra

Casandra Test Code LC01417Version 1 (DRAFT)

Performing Lab

Lab LabcorpLab Test ID 004291CPT Code 82088

Aldosterone, 24-Hour Urine

Clinical Use

Use

Study of adrenocortical-renin-angiotensin system; adrenal cortical function test; evaluate renal hypertension; diagnose Conn syndrome (primary aldosteronism); evaluate hypokalemia with hypertension

Special Instructions

Instructions for suppression or stimulation tests involving serum aldosterone measurement can be found in the online Endocrine Appendix: Aldosterone Suppression. It is crucial to follow the instructions carefully to ensure accurate test results.

Limitations

Urinary aldosterone measurements alone have limited value in diagnosing hyperaldosteronism. Elevated levels warrant further investigation to confirm or rule out hyperaldosteronism. Factors such as diuretics, antihypertensives, and dietary variations impact aldosterone levels, potentially affecting test interpretation.

Test Details

Methodology

Mass Spectrometry

Biomarkers

Aldosterone

Analyte

Aldosterone • Concentration / Level • Quantitative (Continuous) (e.g., copies/mL, % expression)

LOINC Codes

Result Codes

1764-0
1765-7

Result Turnaround Time

4-9 days

Specimen

Urine

Volume

10 mL

Minimum Volume

1 mL

Container

Plastic urine container, no preservative

Collection Instructions

Instruct the patient to void at 8 a.m. and discard the specimen. Then collect all urine including the final specimen voided at the end of the 24-hour collection period (i.e., 8 a.m. the next morning) into the plastic urine container. Screw the lid on securely. Transport the specimen promptly to the laboratory. Container must be labeled with patient's full name, date and time collection started, and date and time collection finished. pH must be 4 to 8.

Patient Preparation

If patient is taking diuretics, antihypertensive drugs, cyclic progestational agents, estrogen, or licorice, results for aldosterone may not be interpretable. Patient should be on a diet containing 135 mmol (3 g) sodium per day for at least two weeks and preferably 30 days prior to testing.