Quantitative Lateral Flow Assays for Salivary Biomarker Assessment: A Review

Abstract

Saliva is an emerging biofluid with a significant number of applications in use across research and clinical settings. The present paper explores the reasons why saliva has grown in popularity in recent years, balancing both the potential strengths and weaknesses of this biofluid. Focusing on reasons why saliva is different from other common biological fluids such as blood, urine, or tears, we review how saliva is easily obtained, with minimal risk to the donor, and reduced costs for collection, transportation, and analysis. We then move on to a brief review of the history and progress in rapid salivary testing, again reviewing the strengths and weaknesses of rapid immunoassays (e.g., lateral flow immunoassay) compared to more traditional immunoassays. We consider the potential for saliva as an alternative biofluid in a setting where rapid results are important. We focus the review on salivary tests for small molecule biomarkers using cortisol as an example. Such salivary tests can be applied readily in a variety of settings and for specific measurement purposes, providing researchers and clinicians with opportunities to assess biomarkers in real time with lower transportation, collection, and analysis costs, faster turnaround time, and minimal training requirements. We conclude with a note of cautious optimism that the field will soon gain the ability to collect and analyze salivary specimens at any location and return viable results within minutes.

Technical considerations to development of serological tests for SARS-CoV-2

“…Thus, finger-stick blood obtained through a lancet, as is common with home glucometers, rather than venous draw which necessitates trained phlebotomists and a clinical setting is an option and is currently used in some EUA tests. Although at present there is only one assay designed for the point-of-care setting with an EUA, ultimately, self-sampling would reduce the risk exposure of healthcare providers to COVID-19 and other communicable diseases and allow for decentralized testing [ 84 ]. The low collection volumes further can facilitate testing in infants and the elderly, yet as most studies reference serum or plasma, the comparison to whole blood does warrant further investigation [ 15 , 78 ].…”

Detection of Zika virus using reverse-transcription LAMP coupled with reverse dot blot analysis in saliva

“…Salivary testing for diagnosis has advantages over other bodily fluids [ 21 , 42 ] but in particular in ZIKV diagnosis it is beneficial because ZIKV RNA can only be detected in the blood from 1–7 days after the clinical onset during acute infection, but persists longer in saliva, semen and urine [ 43 – 45 ] suggesting that saliva could be a preferred specimen to use for ZIKV diagnostics. Drawbacks to saliva as a test matrix are that the concentration is frequently lower than typically found in serum and circadian variations in analyte concentrations can make the sensitivity lower [ 46 ]. However recent development of microfluidic concentrators suitable for diagnostics makes the analysis of nucleic acid targets that are present in low levels [ 47 ] possible.…”

Measuring the Psychobiological Correlates of Daily Experience in Adolescents

“…Consumer market apps have been shown to provide highly inaccurate data (e.g., Alexander, Minhajuddin, & Joshi, ; Plante et al., ) and are currently not recommended for research purposes. However, driven by advances in patient monitoring and medical technologies, it is likely that app‐based measures of psychobiology in ambulatory settings will advance at pace and the recent advances in ambulatory assessments of steroid hormones using lateral flow devices are an example (Miocevic et al., ; Shirtcliff et al., ). In some studies, it may be necessary to develop bespoke applications for data collection; however, translating researcher needs and ideas into app development is not always feasible from a technological or data security perspective (Heron et al., ), and engaging third parties to participate in the development of the application has significant cost implications.…”