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Michael J Wheeler - One of the best experts on this subject based on the ideXlab platform.
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Free Cortisol index as a surrogate marker for serum free Cortisol
Annals of Clinical Biochemistry: International Journal of Laboratory Medicine, 2002Co-Authors: Carel W Le Roux, Sivajenani Sivakumaran, Jamshid Alaghband-zadeh, Waljit Dhillo, May Kong, Michael J WheelerAbstract:Background The biologically active component of a hormone is the unbound or free fraction. Changes in Cortisol-binding protein could give misleading results if only total Cortisol is measured for the interpretation of dynamic function tests. Methods This study aimed to measure serum free Cortisol using a steady-state gel-eltration method and then to evaluate the correlation between the serum free Cortisol and the free Cortisol index (FCI), de ened as serum total Cortisol/Cortisolbinding globulin (CBG).
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Free Cortisol index as a surrogate marker for serum free Cortisol.
Annals of clinical biochemistry, 2002Co-Authors: Carel W Le Roux, Sivajenani Sivakumaran, Jamshid Alaghband-zadeh, Waljit Dhillo, Wing May Kong, Michael J WheelerAbstract:The biologically active component of a hormone is the unbound or free fraction. Changes in Cortisol-binding protein could give misleading results if only total Cortisol is measured for the interpretation of dynamic function tests. This study aimed to measure serum free Cortisol using a steady-state gel-filtration method and then to evaluate the correlation between the serum free Cortisol and the free Cortisol index (FCI), defined as serum total Cortisol/Cortisol-binding globulin (CBG). Forty-eight serum samples from healthy volunteers undergoing a short Synacthen test were analysed for total Cortisol, free Cortisol and CBG. The FCI correlated well with a previously established, but more complex, calculation of serum free Cortisol (R = 0.98, P <0.001) and with measured serum free Cortisol (R = 0.90, P < 0.001). Free Cortisol index is a reliable and user-friendly measure of serum free Cortisol.
Bala Venkatesh - One of the best experts on this subject based on the ideXlab platform.
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Serial changes in plasma total Cortisol, plasma free Cortisol, and tissue Cortisol activity in patients with septic shock: an observational study.
Shock (Augusta Ga.), 2012Co-Authors: Jeremy Cohen, Melissa Lassig Smith, Renae Deans, Carel J. Pretorius, Jacobus P.j. Ungerer, Terrence C. H. Tan, Mark Jones, Bala VenkateshAbstract:Published data on adrenocortical function in septic shock have enrolled patients at various stages of critical illness and predominantly used plasma total Cortisol, with minimal information on serial changes. Moreover, plasma free Cortisol and tissue corticosteroid activity may not be strongly associated; however, few published data exist. The aim of this prospective observational study was to investigate serial changes in plasma total and free Cortisol and tissue Cortisol activity in septic shock. Twenty-nine adult patients admitted with septic shock to a tertiary-level intensive care unit were enrolled. A low-dose corticotropin test was performed on day 1. Plasma total and free Cortisol, cortisone, transcortin, and urinary free Cortisol and cortisone were analyzed on days 1 to 5, 7, and 10. Urinary and plasma Cortisol-cortisone ratios (F:E ratio) were calculated as indices of 11-β hydroxysteroid dehydrogenase 2 and global 11-β hydroxysteroid dehydrogenase activity, respectively. Baseline total and free plasma Cortisol values from 10 healthy control subjects were obtained for comparative analysis. Baseline plasma total and free Cortisol levels were significantly higher than controls (457.8 ± 193 vs. 252 ± 66 nmol/L, P = 0.0002; and 50.83 ± 43.19 vs. 6.4 ± 3.2, P < 0.0001, respectively). Plasma free Cortisol rose proportionately higher than total Cortisol (124% ± 217.3% vs. 40% ± 33.2%, P = 0.007) following corticotropin. Baseline plasma and urinary F:E ratios were elevated over the reference ranges (13.13 ± 1.5, 1.69 ± 2.8) and were not correlated with plasma free Cortisol values (r = 0.2, 0.3 respectively). Over the study period, total Cortisol levels and plasma F:E ratios remained elevated, whereas plasma free Cortisol levels and urinary F:E ratio declined. At baseline, plasma free Cortisol levels were higher in patients who subsequently survived (23.7 ± 10.5 vs. 57.9 ± 45.8 nmol/L, P = 0.04). In septic shock, there is a differential response of plasma total and free Cortisol over time and in response to corticotropin. Changes in plasma and urinary F:E ratios suggest tissue modulation of 11-β hydroxysteroid dehydrogenase activity. Total plasma Cortisol measurements may not reflect the global adrenal response in septic shock.
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characterising adrenal function using directly measured plasma free Cortisol in stable severe liver disease
Journal of Hepatology, 2010Co-Authors: Terrence C. H. Tan, Jeremy Cohen, Linus Chang, A Woodward, Brett Mcwhinney, John Galligan, Graeme A Macdonald, Bala VenkateshAbstract:Background & Aims Adrenal insufficiency (AI) has been reported in patients with advanced liver disease. Diagnosing AI is problematic owing to controversies in using total serum Cortisol as a measure of adrenal function. No published data exist on directly measured plasma free Cortisol (PFC) in patients with liver disease. Methods This prospective study compared serum total and measured plasma free Cortisol to evaluate adrenal function in clinically stable cirrhotic patients and healthy controls. Cortisol levels were measured at baseline and following 250μg corticotrophin. AI was defined by total Cortisol increments (delta Cortisol) of less than 250nmol/L, or a peak total Cortisol under 500nmol/L after cosyntropin. We used a peak plasma free Cortisol concentration of 33nmol/L as the threshold for AI. Results Forty-three consecutive patients and 10 healthy controls were studied. Cirrhotic patients had significantly lower peak (526 vs. 649nmol/L, p =0.004) and delta total Cortisol (264 vs. 397nmol/L, p =0.002) responses compared to healthy controls. However, basal plasma free Cortisol was higher in patients (10.9 vs. 6.4nmol/L, p =0.03), and there were no differences in peak plasma free Cortisol ( p =0.69) between the two groups. The prevalence of AI using total Cortisol criteria was 58% compared to 12% using free Cortisol ( p Conclusion In patients with stable severe liver disease, a significant discrepancy exists between the rates of diagnosis of AI using the total and free Cortisol criteria. We would advise caution in the interpretation of adrenal function testing using total Cortisol measurements in this group.
Philip R. Orlander - One of the best experts on this subject based on the ideXlab platform.
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Salivary Cortisol Can Replace Free Serum Cortisol Measurements in Patients With Septic Shock
Chest, 2011Co-Authors: Rosa M. Estrada-y-martin, Philip R. OrlanderAbstract:Background There is a renewed interest in adrenal function during severe sepsis. Most studies have used total serum Cortisol levels; however, only free serum Cortisol is biologically active. The aim of this study was to determine the validity of salivary Cortisol levels as a surrogate for free serum Cortisol levels during septic shock. Methods Fifty-seven patients with septic shock were studied to determine the correlation between total serum Cortisol and salivary Cortisol to free serum Cortisol levels. Thirty-eight patients were included in the salivary to free serum Cortisol correlation. Salivary Cortisol level was tested by enzyme immunoassay. Serum total Cortisol, free Cortisol, and Cortisol-binding globulin (CBG) levels were determined by liquid chromatography-mass spectrometry, equilibrium analysis, and radioimmunoassay, respectively. Results The mean ± SD age was 56.6 ± 18.5 years. Fifty-seven percent were women. APACHE (Acute Physiology and Chronic Health Evaluation) II score median was 26, Simplified Acute Physiology Score II median was 61, and Sequential Organ Failure Assessment median was 13. The correlation between salivary and free serum Cortisol levels was 0.79 (95% CI, 0.63-0.89; P P Conclusions Salivary Cortisol level can be used as a surrogate of free serum Cortisol level in patients with septic shock with very good correlation. Salivary Cortisol testing is noninvasive, easy to perform, and can be conducted daily. Trial registry ClinicalTrials.gov; No.: NCT00523198; URL: www.clinicaltrials.gov
Carel W Le Roux - One of the best experts on this subject based on the ideXlab platform.
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Free Cortisol index as a surrogate marker for serum free Cortisol
Annals of Clinical Biochemistry: International Journal of Laboratory Medicine, 2002Co-Authors: Carel W Le Roux, Sivajenani Sivakumaran, Jamshid Alaghband-zadeh, Waljit Dhillo, May Kong, Michael J WheelerAbstract:Background The biologically active component of a hormone is the unbound or free fraction. Changes in Cortisol-binding protein could give misleading results if only total Cortisol is measured for the interpretation of dynamic function tests. Methods This study aimed to measure serum free Cortisol using a steady-state gel-eltration method and then to evaluate the correlation between the serum free Cortisol and the free Cortisol index (FCI), de ened as serum total Cortisol/Cortisolbinding globulin (CBG).
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Free Cortisol index as a surrogate marker for serum free Cortisol.
Annals of clinical biochemistry, 2002Co-Authors: Carel W Le Roux, Sivajenani Sivakumaran, Jamshid Alaghband-zadeh, Waljit Dhillo, Wing May Kong, Michael J WheelerAbstract:The biologically active component of a hormone is the unbound or free fraction. Changes in Cortisol-binding protein could give misleading results if only total Cortisol is measured for the interpretation of dynamic function tests. This study aimed to measure serum free Cortisol using a steady-state gel-filtration method and then to evaluate the correlation between the serum free Cortisol and the free Cortisol index (FCI), defined as serum total Cortisol/Cortisol-binding globulin (CBG). Forty-eight serum samples from healthy volunteers undergoing a short Synacthen test were analysed for total Cortisol, free Cortisol and CBG. The FCI correlated well with a previously established, but more complex, calculation of serum free Cortisol (R = 0.98, P <0.001) and with measured serum free Cortisol (R = 0.90, P < 0.001). Free Cortisol index is a reliable and user-friendly measure of serum free Cortisol.
Alan L Rockwood - One of the best experts on this subject based on the ideXlab platform.
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Cortisol and cortisone analysis in serum and plasma by atmospheric pressure photoionization tandem mass spectrometry
Clinical Biochemistry, 2004Co-Authors: Mark M Kushnir, Rebecca Neilson, William L Roberts, Alan L RockwoodAbstract:Objectives: Cortisol metabolism is controlled by 11β-hydroxysteroid dehydrogenase (11β-HSD) isoenzymes, which interconvert Cortisol and cortisone. Accurate measurement of the Cortisol and cortisone concentrations and their ratio provide useful information about 11β-HSD activity. Methods: Cortisol and cortisone were extracted with methyl-tert-butyl ether from 100 μl of serum or plasma. The extract was evaporated, reconstituted with mobile phase, and analyzed by tandem mass spectrometry using a photoionization interface. The transitions monitored were: m/z 363 to 121 and 363 to 97 for Cortisol, 361 to 163 and 361 to 105 for cortisone. Results: Within-run and between-run coefficients of variation were less than 6% and 12%; 14% and 22%; 11% and 21% for Cortisol, cortisone, and their ratio, respectively. The limit of detection was 1 μg/l for Cortisol and 5 μg/l for cortisone. Normal ranges for Cortisol and cortisone concentration and for their ratio in plasma (n = 120) determined as the central 95% were 33–246 μg/l for Cortisol, 8–27 μg/l for cortisone, and 0.081–0.301 for the cortisone/Cortisol ratio. Conclusions: We developed a simple sensitive method for Cortisol and cortisone analysis in plasma and serum that uses a small sample volume. The method is very specific, fast, does not have any known interference, and is useful for diagnosis of variety of disease and pathologic conditions.
