Comparison of total, salivary and calculated free cortisol levels in patients with severe sepsis

BACKGROUND: The purposes of the study were to compare serum total cortisol (STC), salivary cortisol (SaC) and calculated free cortisol (cFC) levels at baseline and after the adrenocorticotrophic hormone (ACTH) stimulation test in patients with severe sepsis (SS) and determine the suitability of use of SaC and cFC levels instead of STC for the diagnosis of adrenal insufficiency (AI) in patients with SS. And secondary aims of this study were to compare these parameters in patients with SS with healthy controls and check their effects on survival status of the patients. METHODS: Thirty patients with SS (15 men and 15 women) were compared with 16 healthy controls. Low-dose (1 μg) ACTH stimulation test was performed to the patients on the first, seventh and 28th days of diagnosis of SS, but in control group, 1 μg ACTH stimulation test was performed only once. STC, SaC and cFC levels were measured during ACTH stimulation test. RESULTS: Patients were categorized as having low or high baseline STC according to a cut-off level of 10 μg/dL. In high STC group, baseline and peak SaC levels were found to be 2.3 (0.2–9.0) and 3.4 (0.5–17.8) μg/dL on D1 and 1.1 (0.8–4.6) and 2.6 (1.3–2.9) μg/dL on D7, respectively. In the control group, baseline and peak SaC levels were 0.4 (0.1–1.4) and 1.1 (0.4–2.5) μg/dL, respectively. Baseline and peak SaC levels after ACTH stimulation were found to be higher in high STC group than in controls, but they were found to be similar in low STC and control groups. In high STC group, cFC levels were 0.3 (0.1–0.3) and 0.4 (0.3–0.7) μg/dL on D1 and 0.2 (0.1–0.3) and 0.4 (0.1–0.7) μg/dL on D7, respectively. In the control group, baseline and peak cFC levels were 1.7 (0.4–1.9) and 1.8 (1.0–6.6) μg/dL, respectively. cFC levels were found to be lower in patients with SS subgroups than in the control group. Baseline and stimulated STC, SaC and cFC levels did not differ according to the survival status. SaC, cFC and STC levels were found to be correlated with each other. CONCLUSIONS: SS is associated with increased SaC, but decreased cFC levels when baseline STC is assumed to be sufficient. When STC level is assumed to be insufficient, SaC levels remain unchanged, but cFC levels are decreased. Lower STC levels is not associated with increased mortality in patients with SS. More data are needed in order to suggest the use of SaC and cFC instead of STC. TRIAL REGISTRATION: ClinicalTrials.gov No: NCT0258943

A Comparison of Capillary, Venous, and Salivary Cortisol Sampling After Intense Exercise

Venipuncture is expensive, invasive, and impractical for many sport-science and clinical-based settings. Salivary free cortisol is often cited as a noninvasive practical alternative. However, when cortisol concentrations exceed the corticosteroid-binding globulin (CBG) point of 500 nmol/L, a lack of agreement between salivary and venous blood cortisol has been found. Alternatively, capillary blood may present a minimally invasive, cost-effective, and practical surrogate for determining cortisol concentration. PURPOSE: The aim of this study was to determine whether cortisol concentrations sampled from capillary blood and saliva accurately reflect those found in venous blood across a large range of concentrations after intense exercise. METHODS: Eleven healthy aerobically trained male subjects were recruited. Capillary, salivary, and venous blood samples were collected before and after (immediately and 5, 10, 15, and 20 min after) a treadmill VO(2) max test. RESULTS: Capillary and venous concentrations increased at a similar rate after exercise (Cohen d.14-.33), increasing up to 15 min postexercise before a decline was seen. Salivary cortisol values increased at a slower rate than venous and capillary cortisol but continued to increase 15 min postexercise (Cohen d .19-.47 and .09-.72, respectively). CONCLUSIONS: Capillary cortisol accurately reflects concentrations assayed from venous blood across a range of values below and above the CBG binding point. Capillary sampling provides a minimally invasive, cost-effective, practical surrogate for assessment of hypothalamic-pituitary-gland function