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18-Hydroxycorticosterone
Test Code94621
CPT Codes
82528
Preferred Specimen
0.5 mL serum collected in a red-top tube (no gel)
Minimum Volume
0.25 mL
Instructions
Collect specimen in a non-additive red-top tube. Spin down immediately and pour off into a 13 x 75 mm plastic tranport tube.
Transport Temperature
Frozen
Specimen Stability
Room temperature: 7 days
Refrigerated: 7 days
Frozen: 28 days
Refrigerated: 7 days
Frozen: 28 days
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Gross and moderate hemolysis • Grossly lipemic • Serum separator tube (SST) • Grossly icteric
Methodology
Liquid Chromatography/Tandem Mass Spectrometry (LC/MS/MS)
FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by FDA. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.
Setup Schedule
Night
Clinical Significance
Primary aldosteronism should be suspected whenever a patient has the triad of hypertension, hypokalemia, and inappropriate renal potassium wasting. The biggest challenge is the differential diagnosis between the more common adrenal adenoma and bilateral hyperplasia. Because adrenal adenomas increase the circulating levels of 18-hydroxycorticosterone (18-OH B), serum levels of 18-OH B may be useful to differentiate them from bilateral adrenal hyperplasia. The cutoff point appears to be about 50 ng/dL of serum. Most values are around 100 ng/dL. The higher the level of this precursor, the greater the possibility that an adrenal adenoma is present.
J Clin Endocrinol Metab. 97: 881-9, 2012.
J Clin Endocrinol Metab. 97: 881-9, 2012.
