Darci Block, Ph.D., discusses saliva testing in AACC’s Clinical Laboratory News

April 7, 2022

Throughout the COVID-19 pandemic, the need for rapid test turnaround has spurred increased interest in saliva testing as a way to arrive at quick, reliable results. But, as a recent article published in the American Association of Clinical Chemistry’s Clinical Laboratory News notes, “Saliva’s use as a health indicator did not start with SARS-CoV-2, nor will it end with this virus.”

The article points to a variety of diseases and conditions where saliva testing may be beneficial, including other infectious diseases, heart disease, human papilloma virus-related head and neck cancers, breast cancers, and lung cancers.

Contributing to the discussion was Darci Block, Ph.D., co-director of the Central Clinical Lab in Mayo Clinic’s Department of Laboratory Medicine and Pathology in Rochester, Minnesota. Dr. Block observes that, although saliva testing may have promise, caution is warranted, as many laboratory tests are currently developed specifically for blood specimens and not other body fluids.

“From a regulatory perspective, manufacturers will indicate testing parameters only for the body fluids that their diagnostics have been approved for,” Dr. Block says. “And most body fluid diagnostics have not been approved for use with saliva.”

She continues: “The way the assay is designed, the concentration of reagents, the amount of sample dilution that happens during testing, is optimized to the indicated testing liquid. So, when you test a sample that doesn't have the exact properties of the indicated testing liquid, you have to wonder what the test results really mean.”

The article goes on to explore ways laboratorians may be able to overcome those obstacles and place saliva testing among the more well-established diagnostic options.

Read the full story here.