Resumen
The collection of salivary cortisol has been chosen as one of the least intrusive, easiest to collect, analyze, and store methods of obtaining information on physiological changes. It is, however, not clear what the best practice is when collecting salivary cortisol from children within the school setting. The aim of this systematic review is to evaluate the feasibility of cortisol collection in schools for future research and to make recommendations for best practice. The review included 25 peer-reviewed articles from seven databases. The hypotheses of the included studies vary, but they all use cortisol as a diurnal, baseline, or acute measure, or to measure the effect of an intervention. Two methods of salivary cortisol collection were preferred by most of the research, i.e., passive drool or cotton Salivettes. The review has concluded that cortisol is a physiological marker that can be successfully measured in school-based research. However, there are discrepancies across studies when evaluating the collection guidelines, protocols, and instructions to participants as well as transparency of the success rate of obtaining all samples. Recommendations are made for future research to address and avoid such discrepancies and improve cross-study comparisons by implementing standard protocol guidelines.