Finding merit in impurity: Designing a cost-effective workflow for saliva genome sequencing

Saliva is often the specimen of choice when selecting a non-invasive sample type. Properly collected, saliva is more stable and convenient to ship than blood. However, DNA extracted from saliva is notorious for its bacterial contamination, with bacterial content as high as 50% in some collections. While a high percentage of bacterial DNA may not interfere with many genetic tests, it constitutes an obstacle for genome sequencing (GS) by consuming valuable sequencing space. We aimed at designing and implementing cost-effective processes that would enable us to offer PCR-free GS using saliva-derived DNA as a clinical test.