Salivary Cortisol Results Obtainable Within Minutes of Sample Collection Correspond With Traditional Immunoassays

Abstract

Purpose Cortisol is frequently assayed as a stress-responsive biomarker which changes over the course of minutes to meet the demands of an individual’s social context. Salivary cortisol is often utilized as a non-invasive sampling methodology which possesses important health implications. A critical barrier to psychobiological research involving salivary cortisol is a time-delay of days to months before cortisol results are obtained via immunoassay, long after the individual is no longer proximate to the social context in which they provided the sample. The current study was designed to address this critical barrier through creation of a lateral flow technology (LFT) cortisol device capable of measuring salivary cortisol within minutes of sample collection. LFT is frequently used within commercial point-of-care settings to obtain rapid answers to the presence/absence of a biomarker. The present study extends LFT into the research domain by presenting performance characteristics of a quantitative LFT which measures salivary cortisol within 20 minutes of sample collection. Methods Saliva samples on N=29 adults (15 males) were obtained in the morning and afternoon using Passive Drool and then the Super•SAL™ Extra Collection Device (hereafter Super•SAL™) and later assayed with LFT and a commercially available enzyme-immunoassay. Findings Results show LFT correlated well with these collection methods (R=.872 with Super•SAL™; R=.739 with Passive Drool, p-values<.0001) and at comparable levels to correspondence of Super•SAL™ with Passive Drool (R=.798, p<.0001) which were measured with the same assay. Implications These results open up an exciting new possibility to integrate this technological advance into stress research, including knowing and potentially changing the individual’s social context in a time-sensitive manner. Methodological improvements such as this have the possibility of refining conceptual models of stress reactivity and regulation.

Effect of Motorcycling on Salivary Noise-Induced Cortisol among Young Motorcyclists

“…Participants were instructed to tilt their head forward for increased secretion of saliva into the oral cavity and transfer directly into a 2 ml saliva collection polypropylene vial (Shirtcliff et al, 2015). Samples that were contaminated with blood were discarded and repeated with 10 minutes break after mouth was rinse with cold water.…”

Salivary Biomarkers in Psychological Stress Diagnosis

“…Cortisol is a steroid hormone (also known as hydrocortisone), produced by the adrenal glands in response to the adrenocorticotropic hormone, and is the final product of the hypothalamic-pituitaryadrenal (HPA) axis [12,14,18,25]. So, cortisol can directly influence the central nervous system, affecting those brain's areas involved in the control of blood pressure [4].…”

“…Circadian rhythm of cortisol secretion, present a typical diurnal variation increase in the early morning hours (cortisol awakening response) and decreases in the evening [7,9,21,[25][26][27]. It is the most frequently investigated stress biomarker, assayed as a stressresponsive biomarker because cortisol is associated with many physiologic and psychobiological processes (cell death, neural development, learning and memory, sleep, metabolism, aging, immune function) [14,18]. Several studies have measured serum, urinary, and salivary cortisol [12].…”

“…Salivary cortisol is often used as a noninvasive sampling method and used as a method to evaluate stress [12,18,21]. It has been successfully used as a biological marker of HPA axis activity in epidemiological studies, increased psychological stress triggers activation of the HPA axis and related hormones [9,18,20].…”

“…These biomarkers provide information about chronic and acute stressors [18]. It is crucial to monitor such biomarkers to prevent diseases, stress-related pathologies, to evaluate behavioral strategies or treatments and improve the quality of life in patients.…”