Serum cortisol

Rapid ACTH Measure serum cortisol Serum cortisol concentration Lalse negative results occur if the ACTH... 

Liquid paraffin cortisol as dansyl hydrazone 10-fold dipping solution, 67% m n-hexane, serum investigations [248, 249]... 

The certification of a cortisol reference serum panel came to an end with the introduction of IRMM/IFCC-45iat the end of 1999. It consists of 34 sera (80-750 nmol/L) and has been certified using ID-GC/MS as a reference method. 

If serum cortisol increase is <9 mcg/dL, then patient may have relative adrenal insufficiency... 

Insulin tolerance Administer insulin IV to Serum cortisol concentration Distinguishes between normal individuals and... 

The unstimulated serum cortisol and rapid ACTH stimulation tests are useful in the diagnosis of adrenal crisis (Table 42-2). The insulin tolerance test is contraindicated owing to preexisting hypoglycemia. The metyrapone test is also contraindicated because metyrapone inhibits cortisol production. 

Assess patients at risk for adrenal insufficiency with screening tests (serum cortisol, plasma ACTH stimulation, etc.)... 

B28. Bladon, P. T., Rowlands, T. E., Whittaker, J. A., and Oakey, R. E., Serum cortisol binding capacity measured with concanavalin A-Sepharose in patients with a recent inflammatory response. Clin. Chim. Acta 253,9-20 (1996). 

Close monitoring of 24-hour urinary free cortisol levels and serum cortisol levels are essential to identify adrenal insufficiency in patients with Cushing s syndrome. Steroid secretion should be monitored with all drug therapy and corticosteroid replacement given if needed. 

High doses of caffeine produce a stresslike neuroendocrine response (Spindel 1984 Spindel et al. 1984). This includes increased levels of corticosterone, jS-endorphin, and decreased serum growth hormone and thyrotropin-stimulating hormone in the rat. However, similar effects are not observed in humans until approximately 500 mg is consumed, the equivalent of 5 cups of coffee. At this dose in humans, elevations are seen in adrenocorticotrophic hormone, jS-endorphin, and cortisol. 

High-dose progestins are used as last-line endocrine therapy [223]. They inhibit the adrenal steroid biosynthesis. The decrease of estrogen levels is comparable to that caused by the administration of aromatase inhibitors. In post-menopausal women, the progestin megestrol acetate (MGA) decreases serum plasma level of DEAH, androstenedione and cortisol to less than 10% [223,224]. 

Several successful attempts were done to transfer classical CEIA to a microchip-based format. This kind of miniaturization is a trend that can overcome the limitations of CE in high-throughput systems. On-chip CE offers both parallel analysis of samples and short separation times. Koutny et al. showed the use of an immunoassay on-chip (32). In this competitive approach fluorescein-labeled cortisol was used to detect unlabeled cortisol spiked to serum (Fig. 8). The system showed good reproducibility and robustness even in this problematic kind of sample matrix. Using serum cortisol standards calibration and quantification is possible in a working range of clinical interest. This example demonstrated that microchip electrophoretic systems are analytical devices suitable for immunological assays that can compete with common techniques. 

Fig. 8 On-chip immunoassay for the quantification of cortisol in serum samples. Fluorescein-labeled cortisol (Ag ) was used in a competitive assay for the detection of unlabeled analyte cortisol. Three replicate injections for each of three samples with cortisol levels as indicated in the figure. Fluorescein was used as an internal standard (I.S.). (Reprinted with permission from Ref. 32. Copyright 1996 American Chemical Society.)...

LB Koutny, D Schmalzing, TA Taylor, M Fuchs. Microchip electrophoretic immunoassay for serum cortisol. Anal Chem 68 18-22, 1996. 

Transcortin acts as a reservoir from which a constant supply of unbound cortisol may be provided to target cells. In addition, when serum albumin levels are low, less circulating cortisol becomes bound, which yields a greater physiological effect. Not only does protein binding control the amount of biologically active cortisol available, but it also reduces the rate at which steroids are cleared from the blood and thus limits steroid suppression of corticotrophin release from the pituitary gland. 

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