A sensitive and reliable cortisol saliva ELISA

Tecan’s new IBL International Cortisol Saliva ELISA kit is an outstanding alternative to the complex and high-priced LC-MS/MS method available at present to analyze cortisol in saliva with accuracy.

  • Regulatory status — EU: CE
  • Method — ELISA
  • Kit size — 12 x 8
  • Standard range — 0.15–30 ng/mL
  • Incubation time — 1 x 2 hours, 1 x 30 minutes
  • Substrate/isotope — TMB 450 nm
  • Specimen/volumes — 50 µL saliva

Advantages of the new IBL Cortisol Saliva ELISA

  • Calibration to the LC-MS/MS reference method: IBL-ELISA = 1.015 x LCMS-0.028, R = 0.99
  • Only six standards and two controls
  • Easy processing
  • Well-defined reference values

Diurnal rhythm

The normal cortisol levels in human saliva are based on the time of day, and the timing of the cortisol peak correlates with the usual wake-up time and not on the actual time of day or daylight.

The new reference ranges are cautiously determined based on 100-day profiles. The reference values starting with batch number ECO137 were considered.

Source: Tecan

Time after awakening (h) Cortisol (saliva) Range - RE52611
(♂/♀; > 6y; n= 100; 5%-95% percentile)
Median Range (µ/dL) Median Range (nmol/L)
(µ/dL) 5% 95% (nmol/L) 5% 95%
Awakening 0.343 0.113 0.803 9.47 3.12 22.17
0.5 0.478 0.200 1.076 13.19 5.52 29.70
1 0.384 0.101 0.936 10.60 2.79 25.82
2 0.234 0.083 0.574 6.44 2.29 15.85
5 0.150 0.074 0.355 4.14 2.04 9.79
8 0.116 0.055 0.314 3.20 1.53 8.67
12 0.082 0.032 0.322 2.26 0.87 8.89

 

A sensitive and reliable cortisol saliva ELISA

Image Credit: Tecan

Sensitive and reliable

The examination of cortisol in the saliva is shown in the diagnostic work-up of clinical issues in different scientific/medical fields, especially psychology, endocrinology, pediatrics, sports medicine, anti-aging medicine and veterinary medicine.

A simple and convenient means to check the function of the adrenal gland is by measuring the free cortisol levels in saliva. Increased or decreased levels of cortisol are found in patients with adrenal dysfunction. Adrenal dysfunction also occurs in various other diseases, like hypothyroidism, fibromyalgia, chronic fatigue syndrome and premature menopause.

The salivary cortisol test can be performed in patients with conditions like fatigue, reduced stress tolerance, depression and sleep disorders.

Standardized reagents

Tecan’s Saliva ELISA product line is made in a way that the major steroids (testosterone, cortisol, progesterone, DHEA) might be processed such that:

  • It is possible to interchange the substrate, washing and stop solutions
  • All kits use the same sample diluent buffer
  • The kits have six standards and two controls
  • The enzyme conjugate, the substrate, and stop solutions are uniformly pipetted with 100 µL
  • Less volume (only 50 µL) of the sample is required

The assays can be carried out in combination due to the similar processing and assembling.