Reliability of the saliva self-sampling with and without supervision

Abstract

One of the least invasive sampling methods suitable for self-sampling is saliva spitting. The aim of this study is to evaluate the suitability of saliva self-sampling for unsupervised testing. Two self-sampling strategies were compared on the basis of visual evaluation of samples, measurement of cortisol levels in samples and questionnaire survey. The saliva samples obtained by supervised self-sampling were found to be fully suitable for further analysis. In contrast, not all saliva samples obtained from unsupervised self-collection can be used: 13% non-compliance with the minimum required sample volume, 8% with some food/drink residues and 26% taken at the wrong day time. About 42% of the unsupervised probands made at least one significant error in the saliva self-collection procedure. These results indicate that the accuracy of the results based on the analysis of samples received from saliva self-sampling is limited. For clinical investigation, the presence of an inner standard (referring to the reliability of the sampling procedure) is required.