Diagnostic Salivary Cortisol EIA 510(K)

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AM/PM Salivary Cortisol Enzyme Immunoassay

Quantitative measurement of salivary Cortisol.

510(k) FDA Approved

631

Enzyme Immunoassay (EIA), Colormetric

0.1 ng/mL – 30 ng/mL

0.05 ng/mL

25 µL

1hr @ Room Temperature

96 wells

450 nm

2° - 8°C

16 Months

Summary and Assay Principle:

Cortisol (hydrocortisone, compound F) is the principle glucocorticoid secreted by the adrenal cortex. Adrenal secretion of cortisol is modulated by a complex negative feedback mechanism involving the central nervous system, hypothalamus, pituitary and adrenals. ACTH released from the pituitary augments adrenal secretion of cortisol. In turn, increased levels of cortisol suppress pituitary secretion of ACTH while falling levels of cortisol are associated with rising levels of ACTH. Normally there is diurnal variation of cortisol with highest values measurable in the morning samples and lowest values obtained in the late afternoon. Cortisol levels rise independently of this circadian rhythm in response to stress or depression. Increased cortisol production is associated with Cushing Syndrome and adrenal tumors while decreased production of cortisol is associated with adrenal insufficiency (Addison’s disease) and adrenocorticotropic hormone (ACTH) deficiency (21, 22, 23, 24).

In blood 90% of the circulating cortisol is firmly bound to cortisol binding globulin (CBG), 7% is weakly bound to albumin and only 1-3% is free or unbound. In saliva the majority of cortisol occurs in the free or unbound form and enters the saliva via intracellular mechanisms (25). Numerous studies consistently report a high correlation between serum and saliva cortisol indicating that salivary cortisol levels clinically confirm levels of cortisol in serum (26, 27, 28).

Assay Principles:

Cortisol calibrators and amounts of Cortisol-enzyme conjugate compete for binding sites on the antiserum. Cortisol from saliva or calibrators reduces Cortisol-enzyme conjugate from binding to the anti-cortisol. The basis of Enzyme immunoassay (EIA) is the quantitative relation between ligand concentration and proportion of cortisol-enzyme conjugate bound to antiserum. Concentration of samples and controls are interpolated from the calibration curve.