Rapid saliva processing techniques for near real‐time analysis of salivary steroids and protein

: Point‐of‐care (POC) measurements using saliva samples have immense potential to assess systemic health and wellbeing, but sample viscosity and contaminants can affect analyses. We sought a portable clean‐up method for whole saliva appropriate for use with POC measurement techniques such as biosensors. Methods : Whole saliva from each of 13 male subjects was split into 5 fractions. Each fraction was treated with a different clean‐up process: a freeze–thaw–centrifuge (FTC) step; centrifugation alone; or passage through a Mini‐UniPrep polyethersulfone filter, cotton Salivette ® , or foam Oracol device. Following clean‐up, each subject's treated saliva fractions were assayed for cortisol, testosterone, dehydroepiandrosterone (DHEA), and proteinconcentrations. The effects of clean‐upmethods on nonspecific binding (NSB) in a biosensor were also assessed. Results : Compared with FTC, no analytes were affected by centrifugation alone. Cotton Salivettes significantly altered all analytes, with increases in cortisol (+64%), testosterone (+126%), and DHEA (off‐scale) levels, and decreased protein (−21%) and biosensor NSB (−75%). Oracol foam devices decreased DHEA levels by 28%. Mini‐UniPrep filtration decreased testosterone (−45%) and DHEA (−66%) concentrations while increasing cortisol (+40%). Conclusion : No method was optimal for all analytes, highlighting the need for validation of saliva treatment methods before their adoption in rapid POC analyses. J. Clin. Lab. Anal. 22:395–402, 2008. © 2008 Wiley‐Liss, Inc.