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EPA Researcher Creates Double Bottom Test Tube to Improve Public Health Monitoring

Published July 13, 2021

The double bottom test tube

Spiritus. A word from the ancient world that means “to breathe”. We now know the word as inspiration. An eruption of imagination or innovation that can lead to wonderful endeavors. For EPA researcher Elizabeth Sams, the journey from imagination to inspiration to invention started with a realization; an idea that was planted in her mind by a desire to improve the quality of test tubes, and finally blossomed into the creation of the double-bottom test tube.

Saliva can be used as a non-invasive tool for monitoring population health. EPA’s epidemiology researchers typically use a sponge on a stick that is placed into a test tube with an ordinary flat lid. When the sample is shipped to a laboratory for testing, the technician must open the tube, invert the sample stick so that the sponge is at the top of the tube for centrifugation. This allows the sample to separate from the sponge and collect at the bottom of the tube. This standard method of sample collection and laboratory processing creates the potential for contamination and increases the time to process samples. This inspired Sams to find a new way to collect and analyze saliva samples.

To improve field collection and processing of saliva samples, Sams invented the double-bottom test tube kit, which can be used for any wet specimen collection. The double-bottom test tube is unique because it replaces an ordinary flat lid with a second test tube bottom on the open end. This is important for in-home collection because participants place the sponge first in the tube. A test tube that is “reversible” allows the saliva to collect at either end without reabsorbing in the sponge or escaping through the lid. Thus, when a sample is sent to a laboratory, a lab technician can simply turn the double-bottom test tube over and centrifuge normally instead of having to open the test tube to invert the collection sponge. This eliminates steps, saves time, and reduces risk of contamination by eliminating the need to open the tube.

The double-bottom test tube is inexpensive, simple to use, and can be safely mailed to homes. It can also collect at least 1mL of fluid and can withstand centrifuge forces of up to 2500 revolutions per minute. The double bottom design can be manufactured and distributed for the same cost as standard cap top tubes, keeping overhead costs the same while saving time and money through faster processing. The streamlined flipping process saves 22 minutes for every 20 tubes, which means a savings of 1.1 minutes per tube. Over 10,000 tubes, a lab would eliminate over 180 hours of labor costs.

Public health and biomarker research are more important than ever. There is a great opportunity to be part of the solution to create faster lab results, lower research costs, and reduce risk of contamination. Through its Federal Technology Transfer Act (FTTA) program, EPA negotiates patent licenses with qualified businesses and individuals who want to commercialize inventions resulting from federally supported research performed at EPA. The double-bottom test tube could be of particular interest to dental, medical, research and public health industries. If interested in licensing the double bottom test tube, please contact EPA through the website: https://www.epa.gov/ftta

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Last updated on August 6, 2024
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