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Urinary Cortisol



96 Wells
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Product Name: Urinary Cortisol

# of Samples: 1 x 96 Assays

Intended Use: Competitive immunoenzymatic colorimetric method for quantitative determination of Cortisol in urine.

Introduction: Cortisol is a steroid hormone released from the adrenal cortex in response to an hormone called ACTH (produced by the pituitary gland), it is involved in the response to stress; it increases blood pressure, 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 utilization and bone metabolism. Cortisol is excreted primarily in urine in an unbound (free) form.
Cortisol is bound, in plasma, from corticosteroid-binding globulin (CBG, transcotin), with high affinity, and from albumin. Only free cortisol is available to most receptors.
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.
The free cortisol fraction represents the metabolically active cortisol. In normal conditions, less then 1% it comes excrete in urines. In pathological conditions (syndrome of Cushing) the levels of free urinary cortisolo are elevate, because the CBG don’t bound the plasmatic cortisol in excess and it was remove with urines.
During pregnancy or estro-progestogen treatment an increase of plasmatic cortisol caused by an increment of the production of the transport protein, but the levels of free urinary cortisol results normal to indicate correct suprarenal functionality.
This test is very useful to estimate the real suprarenal function, because is dose the free cortisol, it is the metabolically active form. Moreover the measurement of free urinary cortisolo is the better parameter for the diagnosis of the Cushing’s syndrome.

Principles of the assay: Microtiter strip wells are precoated with anti-Cortisol antibodies (solid-phase). Cortisol in the sample competes with added horseradish peroxidase labelled Cortisol (enzyme-labelled antigen) for antibody binding. After incubation a bound/free separation is performed by solid-phase washing. The immune complex formed by enzyme-labelled antigen is visualized by adding Tetramethylbenzidine (TMB) substrate which gives a blue reaction product. The intensity of this product is inversely proportional to the amount of Cortisol in the sample. Sulphuric acid is added to stop the reaction. This produces a yellow endpoint colour. Absorption at 450 nm is read using an ELISA microwell plate reader.

Storage and Stability: The reagents are stable up to the expiry date stated on the label when stored at +2...+8 °C in the dark.

Limitations of the Test: Sample(s), which are contaminated microbiologically, should not be used in the assay. Highly lipemeic or haemolysed specimen(s) should similarly not be used. It is important that the time of reaction in each well is held constant for reproducible results. Pipetting of samples should not extend beyond ten minutes to avoid assay drift. If more than one plate is used, it is recommended to repeat the dose response curve. Addition of the substrate solution initiates a kinetic reaction, which is terminated by the addition of the stop solution. Therefore, the addition of the substrate and the stopping solution should be added in the same sequence to eliminate any time deviation during reaction. Plate readers measure vertically. Do not touch the bottom of the wells. Failure to remove adhering solution adequately in the aspiration or decantation wash step(s) may result in poor replication and spurious results.
If computer controlled data reduction is used to calculate the results of the test, it is imperative that the predicted values for the calibrators fall within 10% of the assigned concentrations.

References Foster, L. B. and Dunn, R.T. (1974) Clin. Chem 20 (3), 365.De Lacerda, L., Kowarski, A., and Migeon, C.J. (1973) J. Clin. Endocr. and Metab 36, 227.Rolleri, E., Zannino, M., Orlandini, S. and Malvano, R. (1976) Clin chim Acta 66, 319.Kobayashi, Y. et al. (1978) Steroids 32 (1), 137 – 44.Arakawa, H., Maeda, M., Tsuji, A. (1979) Anal. Biochem. 97, 248.

Additional Information

Name Urinary Cortisol
Related Product Names Urinary Cortisol
Datasheets / Downloads Click here to download product manual.
Storage The reagents are stable up to the expiry date stated on the label when stored at +2...+8 °C in the dark.
Intended Use Research Use Only