Timo Deutschbein

Diagnosis of secondary adrenal insufficiency in patients with hypothalamic–pituitary disease: comparison between serum and salivary cortisol during the high-dose short synacthen test

OBJECTIVEnAccurate assessment of adrenal function is essential in patients with hypothalamic-pituitary-adrenal (HPA) disease. The measurement of salivary cortisol (SaC) instead of serum cortisol (SeC) offers several advantages, such as the determination of the free hormone. We evaluated the diagnostic value of SeC and SaC both unstimulated and during a high-dose short synacthen test (HDT) in comparison to the insulin tolerance test (ITT).nnnDESIGNnComparative study between 2005 and 2007.nnnMETHODSnFifty-five patients with HPA impairment and 21 healthy controls were enrolled. Samples were collected in the early morning and over 120 min during the HDT. Receiver operating characteristic analysis revealed individual thresholds for four HDT periods (0-30, 0-60, 0-90, and 0-120 min).nnnRESULTSnThe ITT identified 30 subjects as adrenal insufficient. With respect to the four HDT periods, sensitivity and specificity were 67-79% and 71-88% for SeC, compared with 63-72% and 72-86% for SaC. If upper and lower thresholds (with specificities >95%) were applied, patients were diagnosed in 40-45% by SeC and in 25-31% by SaC. The combination of basal cortisol and HDT allowed a diagnosis in 47-49% (SeC) and in 42-45% (SaC) respectively.nnnCONCLUSIONnWe suggest the determination of basal SeC or SaC as first-line test. In comparison to the ITT, the HDT has only limited value in screening for alterations of the HPA axis. If the HDT is performed, sampling may be limited to 30 min post-synacthen, using either SeC or SaC. Due to the ease of collection and the independence of binding proteins, SaC may be preferable.

Influence of various confounding variables and storage conditions on metanephrine and normetanephrine levels in plasma

Objectiveu2002 Measurements of plasma free metanephrines have been advocated as first‐line tests for phaeochromocytoma. The aim of the study was to assess the impact of potential confounding variables.

Late-night and low-dose dexamethasone-suppressed cortisol in saliva and serum for the diagnosis of cortisol-secreting adrenal adenomas.

OBJECTIVEnIn patients with adrenal incidentalomas, hormonally active masses need to be considered, particularly cortisol-producing adenomas (CPA), aldosterone-producing adenomas, and pheochromocytomas. The screening for hypercortisolism relies on confirming excess cortisol secretion and insufficient suppression after dexamethasone. Because of its high correlation with free cortisol and its stress-free collection, salivary cortisol (SaC) may offer advantages over serum cortisol (SeC). We evaluated the value of SaC and SeC for the diagnosis of CPA. Design Comparative study between 2001 and 2006.nnnMETHODSnThirty-eight patients with confirmed CPA were compared with 18 healthy subjects as well as 48 control patients suffering from aldosterone-producing adenomas (n=13), pheochromocytomas (n=16), or nonfunctioning adenomas (n=19). Sampling of saliva and serum was performed at 2300 and at 0800 h following low-dose dexamethasone suppression. Receiver operating characteristics analysis was used to calculate thresholds with at least 95% sensitivity for CPA.nnnRESULTSnRegarding the cutoffs for late-night cortisol, SaC (4.8 nmol/l, sensitivity 97%, specificity 69%) was slightly more specific than SeC (115 nmol/l, sensitivity 97%, specificity 63%). In contrast, the cutoff for dexamethasone-suppressed SaC (3.7 nmol/l, sensitivity 97%, specificity 83%) was slightly less specific than SeC (94 nmol/l, sensitivity 97%, specificity 88%). However, the latter cutoffs demonstrated greater specificity when compared with the cutoffs for late-night cortisol.nnnCONCLUSIONnThe diagnostic accuracy of SaC is as good as SeC. Owing to its higher specificity, dexamethasone-suppressed cortisol is preferable to late-night cortisol when screening for Cushings syndrome in patients with adrenal incidentalomas.