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Diagnostic value of salivary cortisol in Cushing's syndrome (CS)
Author(s) -
Cardoso Estela M. L.,
Arregger Alejandro L.,
Tumilasci Omar R.,
Contreras Lilia.
Publication year - 2009
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/j.1365-2265.2008.03381.x
Subject(s) - medicine , endocrinology , intraclass correlation , saliva , urine , radioimmunoassay , reproducibility , cushing syndrome , dexamethasone , chemistry , chromatography
Summary Objective The diagnosis of Cushing's syndrome (CS) remains a challenge in clinical endocrinology. The aim of this study was to determine the reproducibility and diagnostic value of late‐night salivary cortisol (SAF 23 ) for CS and its utility along the follow‐up of treated patients. In addition, using the same radioimmunoassay reactives, the cut‐off values for saliva and serum cortisol, assessed synchronically after the overnight 1 mg dexamethasone suppression test (DST), were defined. Design Twenty‐one patients with confirmed CS and 121 volunteers were studied. All the subjects collected 24‐h urine for cortisol (UFC). On the same day whole saliva was obtained from the subjects at 23 h for SAF 23 . The intraclass coefficient of correlation (ICC) of SAF 23 was estimated in 47 subjects (21 CS and 26 C). At 8 h, after DST, simultaneous saliva and serum samples for cortisol (SAF dex and F dex , respectively) were obtained in 51 subjects (17 CS and 34 C). After specific therapy, 18 patients with CS were followed with SAF 23 measurements. SAF and F were expressed as n m . Results The intraclass coefficient of correlation of SAF 23 was 0·89 in CS and 0·83 in C. SAF 23 > 3·8 n m showed a sensitivity and specificity of 100% and 97·5%, respectively, for diagnosing CS. SAF 23 correlated positively with UFC ( r = 0·685; P = 0·0001). After DST, SAF dex significantly correlated with F dex ( r = 0·61, P < 0·0001). A cut‐off value of SAF dex > 2·0 n m and F dex > 50·0 n m detected CS with 100% sensitivity and specificity. After successful surgical therapy, 13 patients with CS had SAF 23 levels < 3·8 n m (1·4 ± 0·8 n m ). Conclusions SAF 23 and SAF dex seem to be good screening tools based on their noninvasive nature, remarkable reproducibility and diagnostic performances.