Cortisol ELISA for serum or plasma 10-500ng/ml Dialab

Cortisol is a steroid hormone released from the adrenal cortex in response to a hormone called ACTH (produced by the pituitary gland), it is involved in the response to stress; it increased blood pressue, blood sugar levels, may cause infertility in women, and suppresses the immune system.

Cortisol acts through specific intracellular receptors and has effects in numerous physiologic systems, including immune function, glucose-counter regulation, vascular tone, substrate utilisation and bone metabolism. Cortisol is excreted primarily in urine in an unbound form. Cortisol is bound, in plasma, to corticosteroid binding globulin (CBG) with high affinity and to albumin. Generally only free cortisol is available to receptors. The amount of cortisol present in serum undergoes diurnal variation, with the highest levels present in the early morning, and lower levels in the evening, several hours after the onset of sleep. These normal endogenous functions are the basis for the physiological consequences of chronic stress – prolonged cortisol secretion causes muscle wastage, hyperglycaemia, and suppresses immune/inflammatory responses. The same consequences arise from long-term use of glucocorticoid drugs.


Between 8.00am -10.00am: 60-230 ng/ml
4.00pm: 30-150 ng/ml
Patient treated with ACTH: 280-600 ng/ml
Patient treated with dexamethasone: 0-50 ng/ml

This assay is intended for the quantitative determination of cortisol in human serum or plasma for diagnostic use. This 96 well ELISA can provide up to 40 patient tests. Cortisol in the sample competes with horseradish peroxidase (HRP) labelled cortisol for binding onto the limited number of anti-cortisol IgG coated on the microplate. After incubation, the bound/free separation is performed by a simple- solid-phase washing. The enzyme in the bound-fraction reacts with the substrate to develop a blue colour which changes to yellow on addition of the stop solution. The colour intensity, as determined by reading absorbance at 450nm, is inversely proportional to the concentration of cortisol in the sample.

Kit contents:
Antibody coated Microtiter wells (Anti-cortisol IgG): 12x8 well strips
Calibrator set (0.0; 10, 50, 150, 500 ng/ml x 1.0ml)
Enzyme Conjugate (Anti-Cortisol-HRP): 1x21ml
Substrate Solution (H₂O₂-TMB 0.26g/L): 1x15ml
Stop Solution (Sulphuric Acid 0.15mol/L): 1x15ml
Wash Buffer 10X (0.2M Phosphate buffer, pH 7.4) : 1x50ml
Sample volume: 20µl human serum or plasma to be run in duplicate
Incubation time: 75 minutes (60 min at room temperature, 15 min in the dark at room temperature)
Measuring range: 0 - 500.0 ng/mL
Sensitivity: 2.44ng/ml
Specificity: Cortisol 100%, Prednisolone 46.2%, 11-Deoxycortisol4%, 11αOH Progesterone 1%, DHEA 0.05%, Progesterone < 0.1%
Store at 2-8°C.