Determination of Multi-Steroid Profiles of Cats With Hyperaldosteronism or Other Diseases: A Retrospective Study

Multi-steroid profiles are proven to help with the diagnostic approach to adrenal disorders in humans.

Compare liquid chromatography tandem mass spectrometry (LC-MS/MS) and radioimmunoassay (RIA) measurement of aldosterone in feline blood samples. Evaluate multi-steroid profiles in cats with hyperaldosteronism.

Client-owned cats with low/normal aldosterone by RIA (low aldo, n = 15), high aldosterone by RIA (high aldo, n = 6) and overt primary hyperaldosteronism (PHA, n = 6).

Exploratory retrospective case-control study. Feline blood multi-steroid profiles were analyzed with LC-MS/MS and compared with results from a commercially available RIA in widespread clinical use.

Aldosterone measurement by LC-MS/MS and RIA was strongly correlated (r = 0.93, p < 0.001) but showed a bias of 56 (95% CI: 104-7) pmol/L, with RIA giving higher values. Creatinine concentration was not significantly associated with the discrepancy between methods (p = 0.95). Cats with PHA had significantly lower serum concentrations of cortisol and glucocorticoid precursors (17-hydroxyprogesterone, 11-deoxycortisol), testosterone, and significantly higher dihydrotestosterone and 5α-dihydroprogesterone concentrations than the low aldo group. Pregnenolone concentrations were significantly lower in the PHA group than in the high aldo group.

Quantification of aldosterone by either LC-MS/MS or RIA is adequate for PHA diagnosis in the clinical setting, with appropriate method-specific reference intervals. Cats with PHA had different concentrations of some steroids compared with the control groups, but overt steroid excess (other than aldosterone) was not observed.