Hey Ya'll,
I am wanting to test salivary cortisol levels in my participants. its a lab value and I do not know if we need to answer validity and reliability questions?
I could not find articles that discussed it? what is your input considering its a scientific procedure not really a scale? If I do need it, do you have any useful resource for me?
Would I need IRB approval for a study that requires salivary sample?
thank you
Hi Katherine, you would need IRB approval to collect saliva samples.
Saliva can be difficult to measure by ELISA, so unless you or your colleagues have experience with saliva samples it might be worth sending them away for specialized analysis. We have used IISBR at UC Irvine previously and they've been great.
Whether you decide to measure cortisol yourself or send samples out, the cort ELISA should be validated and have the sensitivity, specificity, validity etc. established by the manufacturer. These are important for the same reasons as scales (i.e. does it measure what we think it measures, and how accurately?)
Here's an article in which we've described this info for cort from the manufacturer (Salimetrics): DOI: 10.1002/jts.22261
Cortisol is also diurnal so it's also important to collect your samples at the same time each day (ideally early AM), and note the flow rate.
Sarah Hellewell thank you for your help! So just to confirm that I understan, we are def sending them to the lab To be handled correctly! so In order for me to know the validity and reliability I must select a specific swap brand and look on their website?
thank you
We have a long-lasting experience and expertise with Cortisol saliva exams over the day (we call it CDP = Cortisol day profile). We use salivettes as a proven device for sampling saliva at 8, 14 and 20 h. The daily assessment of CDP has several advantages eg. the assessment of biorhythm, daily influences (stress, work, sport) and the total production of cortisol during the day (AUC = Area Under the Curve). Saliva Cortisol is analyzed fully automatically in the laboratory using a CLIA (chemiluminescence assay). Saliva cortisol's own reference values were obtained by CDP from 3004 healthy men and women. No gender-specific differences were discernible.
For a modern neurobiological stress analysis, we recommend the integral stress test (IST), which consists of psychological evaluation (via a protected online access), determination of cortisol TP, neurotransmitters (noradrenaline, dopamine, serotonin) in the 2nd morning urine and a 3-day heart rate variability (HRV) analysis. With this test (IST), we can reliably identify causes of stress and specifically advise appropriate procedures (coaching, psychotherapy, stress management according to the BERN concept and substitutions) for appropriate therapies.
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