Background: A method for the measurement of five important serum and urinary corticoids on the syndrome of mineralcorticoid excess is reported. The methodology was combined gas chromatography-mass spectrometry (GC-MS) with selected ion-monitoring mode.
Methods: After extraction with a solid-phase cartridge using an Oasis HLB copolymer, the residues were derivatized with a mixture of N-methyl-N-trimethylsilyltrifluoroacetamide/ammonium iodide/dithioerythritol (1000:4:5, v/w/w), and analyzed.
Results: The linearity as the regression coefficients were >0.979 over a range of 1-500 ng/ml, and limit of detection ranged from 1 to 3 ng/ml while their analytical recoveries varied in the range of 75.7-94.9%. The overall precision (% CV) of the method were 3.2-7.2% and 3.6-6.3% for serum and urine, respectively. The accuracy expresses as % bias ranged from -4.1 to 6.4%. This assay was used on two patients with hypokalemic hypertension, and may be useful in ruling out mineralcorticoid excess (AME) type 1 or 2.
Conclusions: The present GC-MS technique may be useful to differentiate between the syndrome of AME and other hypertensive diseases with clinical features suggestive of mineralcorticoid excess because of the assay's reliablity and precision.