From May 31st to June 2nd, 2023, the fourth Saliva and Liquid Australia (SALSA) conference was held both remotely and in-person at Waurn Ponds Estate in Victoria, Australia. SALSA is an international, Australian-based conference that highlights technological innovation in saliva and liquid bio-sampling for applications in human health and diseases. Annually, SALSA brings together a broad range of experts from academia, diagnostics, and biotechnology industries. 

Our team from DNA Genotek Inc.—a subsidiary of OraSure Technologies, Inc.—was pleased to be able to attend the event in person! Below, we are revisiting some of the key themes and takeaways from the conference, including a complete summary of the presentation given by David Francis, Laboratory Head of Molecular Cytogenetics at Victorian Clinical Genetics Services (VCGS) in Australia.

The potential for saliva and liquid bio-sampling 

Consisting of eight sessions across the first two days of June, the SALSA 2023 conference was convened by the conference chair, Professor Jeffrey Craig, from Deakin University School of Medicine, Australia. Recognizing the utility and value of saliva and liquid bio-sampling, several presentations—including both national and international keynote addresses—were focused on saliva and other biological fluids (e.g., blood, urine, sperm, breast milk, etc.) and how these biofluids can be used for biomarker detection, diagnostic purposes, and/or risk assessment for several different diseases.  

Multiple presentations touched on the value of saliva for COVID-19 clinical diagnostic testing and how saliva has emerged as a critical biofluid as a result of the COVID-19 pandemic. Already, because of the global COVID-19 pandemic, substantial progress has been made in recognizing at-home self-collection and self-testing. In the international plenary opening keynote address—the first presentation kick-starting the conference—Dr. Anne Wyllie of the Yale School of Public Health, U.S.A, described how saliva is a reliable sample type for sustainable surveillance and outbreak response for several different viruses. Notably, Dr. Wyllie emphasized that no single sample type is considered “perfect”, but that this should not limit our use of different sample types.  

Saliva sampling shows increased technical and clinical utility over blood sampling in genetic investigation of syndromic intellectual disability 

Presented by David I. Francis
Laboratory Head of Molecular Cytogenetics at VCGS   

David started off his presentation by addressing one of the most frequently asked questions in terms of liquid sample type: Why use saliva if blood is the current gold-standard liquid sample type? He reviewed the composition of saliva (human lymphocytes and fibroblasts) and several applications where saliva was already used successfully (e.g., pharmacogenomics, drug testing, viral/bacterial testing).  

David went on to provide some background on how saliva was introduced in 2014 at VCGS, collected using DNA Genotek’s ORAcollect™ devices. He also explained that microarrays were the predominant type of test run at the VCGS and how ~23,000 saliva-based microarray tests have currently been run over the last 8 years at VCGS.   

For the rest of his presentation, David went over the clinical utility and technical performance of saliva versus blood in their recent research investigating syndromic intellectual disability. Saliva samples were collected from pediatric patients using ORAcollect™ for pediatrics (OC-175) devices which are optimized for the assisted collection of saliva. Over the course of their years of saliva sampling, David and his colleagues ended up with 370 individuals who had provided both saliva and blood samples. These samples could thus be directly compared to assess the detection of mosaic tissue versus non-mosaic tissue copy number variants (CNVs) from a saliva or blood sample of the same individual. Notably, 20 mosaic cases showed CNV abnormalities in the saliva sample, but these same abnormalities were not detectable in the blood sample. Highlighting a specific mosaic case in a patient with epilepsy and syndromic intellectual disability, David showed data that illustrated that fibroblast cells were being detected in the saliva sample, but not in the blood sample. 

In summary, two of the key takeaways from David’s presentation were that: 

1. There was no difference between the rates of CNV abnormalities in large datasets of saliva or blood samples, suggesting similar technical performance:

• Saliva gives less DNA yield compared to blood  

• Failure rate in acquiring DNA from saliva is slightly higher than blood 

2. Saliva samples showed increased detection for clinically significant mosaic genomic abnormalities related to syndromic ID, demonstrated a distinct clinical utility for saliva over blood 

To learn more about the research presented by David Francis and the details on how saliva outperformed blood sampling in this particular scenario, see his recent 2023 research article, published in the European Journal of Human Genetics.  

Final thoughts and future outlook 

The SALSA 2023 conference is a unique and important gathering for exchanging ideas and fostering innovation and collaboration in terms of biological sampling and diagnostic testing. Notably, several presentations went beyond human genomics, and touched on the value of surveying the oral microbiome from saliva samples, including potential bacterial biomarkers for oral/dental hygiene or neonatal health assessment. 

DNA Genotek is proud to offer products that support both clinical and/or research needs. If you are interested in exploring or expanding your total nucleic acid sample collection capabilities (i.e., DNA and/or RNA), for either human host or microbial collection, learn more about our new OMNIgene™•SALIVA DNA and RNA device on our website or send us an email at info@dnagenotek.com.