Diagnostic performance of a newly developed salivary cortisol and cortisone measurement using an LC–MS/MS method with simple and rapid sample preparation

Abstract

Late-night salivary cortisol and cortisone are useful parameters for the diagnosis of hypercortisolism. Using samples obtained from patients where the diagnosis of hypercortisolism is extremely challenging cut-off values for midnight salivary cortisol and cortisone measured by LC-MS/MS method were established.

Bedtime Salivary Cortisol and Cortisone by LC-MS/MS in Healthy Adult Subjects: Evaluation of Sampling Time

“…Although specific bedtimes were not given, this study was from Italy where, typically, bedtime is considerably later than the Midwestern United States [38], which makes this issue less of a confounder than in our patients with a bedtime significantly earlier than 2300 hours. A study from Budapest, Hungary, found consistently higher “late-night” (without defining the sampling time) immunoassay cortisol and LC-MS/MS cortisol and cortisone results compared with our results [21]. Investigators should be encouraged to record and report actual sampling times when doing these types of studies.…”

“…We have demonstrated that (i) healthy adult subjects can sample at their normal bedtime and achieve lower salivary cortisol results than if forced to remain awake until 2300 hours or later [21, 30], (ii) that a modified LC-MS/MS method using only 50 µL of saliva performs well in the measurement of salivary cortisol and cortisone, (iii) that the ratio of cortisol to cortisone is higher in the morning when both cortisol and cortisone concentrations are greater (compared with the evening) and that this ratio is positively correlated with salivary cortisol, (iv) morning cortisol and cortisone at awakening are quite variable and unlikely to be useful by themselves for the diagnosis of adrenal insufficiency, and (v) there was no effect on late-night cortisol or cortisone based on sex or age in adults <65 years of age.…”

“…The measurement of bedtime salivary cortisone may improve sensitivity and specificity for Cushing syndrome [21, 22]. However, the improvement would be, at most, 5% to 8% above the already excellent sensitivity and specificity (≥90%) [12].…”

“…water (150 µL) and 10 µL of 138 nmol/L deuterium-labeled cortisol-d4 and cortisone-d7 (IsoSciences LLC, Ambler, PA) then extracted with 2 mL of methyl tert -butyl ether. We chose to sacrifice some sensitivity to use only 50 µL of saliva as compared with 100 to 500 µL typically used [16, 17, 21, 22, 35] because it is common for us to receive clinical samples with <100 µL of saliva. The ether phase was then transferred and evaporated to dryness under nitrogen in a 35°C water bath and reconstituted in 100 µL of 50:50 (volume-to-volume ratio) methanol-to-water ratio.…”

Comparing Glucose Concentration Among Six Saliva Collection Methods In The Newly Developed Saliva Glucose Detection System

“…All saliva glucose were collected in the same clinical room and at the same time in the four time periods of 9:00-9:30, 11:00-11:30, 14:00-14:30 and 17:00-17:30. After completing the above steps, the cotton swab soaked was spit with saliva back into the collection tube, then the saliva was collected and weighed with electronic-balance (denoted as Q 1 after centrifugation [21], and it was frozen directly at -20°C for testing after collection [22]. The saliva ow rate (SFR) re ected the amount of saliva, and calculated as in Eq.…”