Abstract INTRODUCTION AND AIM: As initial screening for Cushing's syndrome (CS), The Endocrine Society guidelines recommend one of the following: the 1-mg dexamethasone suppression test (DST) or late-night salivary cortisol (LNSC) or urinary free cortisol (UFC) measurement. We examined the diagnostic performance of the above-mentioned tests in a series of patients. MATERIALS AND METHODS: We retrospectively analyzed 137 patients with clinical conditions suggestive of hypercortisolism: 38 with confirmed CS diagnosis and 99 without (termed non-CS). UFC was measured by liquid chromatography tandem-mass spectrometry, whereas LNSC by the radioimmunometric method and serum cortisol were measured by a chemiluminescence immunoassay. RESULTS: Comparing CS vs non-CS, a cutoff of 138 nmol/L after 1-mg DST revealed the best specificity (SP; 97%), whereas the 50-nmol/L cutoff confirmed the best sensitivity (SE; 100%); the SE and SP for LNSC greater than 14.46 nmol/L were, respectively, 84% and 89%, whereas the SE and SP for UFC greater than 170 nmol per 24 hours, they were 97% and 91%. Overall, UFC revealed both a combined higher positive and a lower negative likelihood ratio among first-line tests (respectively 10.7 and 0.03). Computing a receiver-operating curve -contrast analysis to compare the power of each single test with that of the others, alone or combined (DST+LNSC, DST+UFC, and LNSC+UFC) or with that of all the tests together (DST+LNSC+UFC), the UFC assay was at least as good as all the other possible combinations. CONCLUSIONS: Measuring UFC by liquid chromatography tandem-mass spectrometry achieves the best accuracy in diagnosing CS among patients presenting with suspected hypercortisolism.

Screening tests for cushing's syndrome: Urinary free cortisol role measured by LC-MS/MS

CECCATO, FILIPPO;BARBOT, MATTIA;ZILIO, MARIALUISA;FRIGO, ANNA CHIARA;ALBIGER, NORA MARIA ELVIRA;CAMOZZI, VALENTINA;ANTONELLI, GIORGIA;PLEBANI, MARIO;MANTERO, FRANCO;BOSCARO, MARCO;SCARONI, CARLA
2015

Abstract

Abstract INTRODUCTION AND AIM: As initial screening for Cushing's syndrome (CS), The Endocrine Society guidelines recommend one of the following: the 1-mg dexamethasone suppression test (DST) or late-night salivary cortisol (LNSC) or urinary free cortisol (UFC) measurement. We examined the diagnostic performance of the above-mentioned tests in a series of patients. MATERIALS AND METHODS: We retrospectively analyzed 137 patients with clinical conditions suggestive of hypercortisolism: 38 with confirmed CS diagnosis and 99 without (termed non-CS). UFC was measured by liquid chromatography tandem-mass spectrometry, whereas LNSC by the radioimmunometric method and serum cortisol were measured by a chemiluminescence immunoassay. RESULTS: Comparing CS vs non-CS, a cutoff of 138 nmol/L after 1-mg DST revealed the best specificity (SP; 97%), whereas the 50-nmol/L cutoff confirmed the best sensitivity (SE; 100%); the SE and SP for LNSC greater than 14.46 nmol/L were, respectively, 84% and 89%, whereas the SE and SP for UFC greater than 170 nmol per 24 hours, they were 97% and 91%. Overall, UFC revealed both a combined higher positive and a lower negative likelihood ratio among first-line tests (respectively 10.7 and 0.03). Computing a receiver-operating curve -contrast analysis to compare the power of each single test with that of the others, alone or combined (DST+LNSC, DST+UFC, and LNSC+UFC) or with that of all the tests together (DST+LNSC+UFC), the UFC assay was at least as good as all the other possible combinations. CONCLUSIONS: Measuring UFC by liquid chromatography tandem-mass spectrometry achieves the best accuracy in diagnosing CS among patients presenting with suspected hypercortisolism.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11577/3168067
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