thesized and secreted from the zona glomerulosa of the A high-performance liquid chromatography -atmoadrenal cortex. Its primary physiological function is to spheric pressure chemical ionization -tandem mass regulate the metabolism of sodium and potassium ions, spectrometry (HPLC-APCI-MS/MS) reference method by stimulating the reabsorption of sodium, in exchange for the quantitation of aldosterone in serum and for potassium and hydrogen ions, in the distal tubules plasma has been developed. Samples were extracted of the kidneys (1). Aldosterone concentration affects with dichloromethane/diethyl ether, containing fluextracellular fluid volume and blood pressure. Hyperalmethasone as internal standard (IS). Chromatography dosteronism is a well-defined chemical disorder and a was performed on a phenyl column using 50 mM ammorecognized cause of hypertension (2), making aldostenium formate (pH 7.1)/methanol (50/50, v/v) as mobile rone quantitation imperative for clinical diagnosis. The phase. Analysis was in negative-ionization mode by sealdosterone concentrations in human serum, plasma, lected reaction monitoring (aldosterone m/z 359.2 r and urine are relatively low, ranging from 20 to 100 331.2; IS m/z 455.0 r 379.0). The assay was linear over pg/mL in the serum of normal subjects (3). This creates the range 15-500 pg/mL, with limits of detection and a need for an accurate and sensitive assay of aldostequantitation of 10 and 15 pg/mL, respectively. Imprecirone.
sions of the assay at 15, 20, 150, and 450 pg/mL were Antibody-based methods such as radioimmunoassay 18.5, 8.8, 10.6, and 9.5%, respectively. The accuracy of (RIA) 2 and enzyme-linked immunosorbent assay the method ranged from 93.1 to 98.9% with absolute (ELISA) have traditionally been used for corticosteroid recoveries between 84.0 and 91.3% (aldosterone) and analysis due to their sensitivity. However, the clear 88.0 and 92.3% (IS). We present a case study of a patient disadvantage of these methods is their potential to admitted, with suspected primary hyperaldosteronoverestimate due to cross-reactivity of the antiserum ism, on the basis of a high radioimmunoassay (RIA) aldosterone concentration. The results suggest that with other endogenous and exogenous compounds (4-RIA was unreliable, causing unnecessary patient dis-7). Recent optimizations in extraction procedures, colcomfort and a costly 6-day hospital stay. The specific umns, and mobile-phase compositions have made chro-HPLC-API-MS/MS assay described offers the sensimatographic analysis of corticosteroids possible (8). tivity and accuracy required to assess abnormal aldo-Several papers report gas chromatography-mass specsterone production in hypertensive patients. ᭧ 1997 trometry (GC-MS) (4, 9), gas chromatography-tan-Academic Press dem mass spectrometry (10), high-performance liquid chromatography-mass spectrometry (HPLC-MS) (4-6, 11-15), and high-performance liquid chromatogra-Aldosterone (11b,21-dihydroxy-3,20-dioxo-pregn-4phy-tandem mass spectrometry (HPLC-MS/MS) (16) en-18-al) is an endogenous mineralocorticosteroid synmethods for the analysis of steroids in urine, plasma, serum, and perfusate media. The improved specificity