THE COMBINATION OF CLASSICAL TESTS AND METHODS OF CHROMATOGRAPHY FOR LABORATORY DIAGNOSTICS OF CUSHING’S SYNDROME OF DIFFERENT GENESIS

Immunochemical methods of analysis are traditionally used for diagnosis of various forms of Cushing's syndrome (CS). In the presence of boundary values of hormonal parameters, doubtful situations, a combination of changes both in pituitary and in adrenal glands, it is useful to determine additional differential diagnostic criteria for the diagnosis of various forms of CS. Urinary steroid profiles (USP) were analyzed by gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC) for 38 females with adrenal Cushing's syndrome (CSA), 42 females with pituitary CS (CSP) and 25 healthy females (control group). An increase of free cortisol/free cortisone ratio in the urine (UFF/UFE) for CSP patients in comparison of CSA was obtained by HPLC method. Decreased urinary excretion of UFF and UFE by more than 60% after the 8 mg dexamethasone suppression test had 100% sensitivity and specificity of more than 90% for the diagnosis of CSP. GC-MS method in patients with CSA and CSG revealed the peculiarities of androgens, progestins and glucocorticoids metabolism which leaded to obtain specific USP for CS of different genesis. Increased urinary excretions of dehydroepiandrosterone and its metabolites, metabolites of androstenedione, the ratio of sum of cortisol and cortisone tetrahydrometabolites to tetrahydro-11-deoxycortisol (more then 36) in CSP patients compared with CSA are additional signs for differential diagnosis of these diseases. The combination of classical tests and USP obtained by HPLC and GC-MS methods increased the sensitivity and specificity of differential diagnosis of CSA and CSP.