Technique could increase sensitivity of nasal swab tests up to tenfold through simple software updates — ScienceDaily

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A multidisciplinary research team at the National Institute of Standards and Technology (NIST) has developed a way to increase the sensitivity of the primary test used to detect the SARS-CoV-2 virus, which causes COVID-19. Applying their findings to computerized test equipment could improve our ability to identify people who are infected but do not exhibit symptoms.

The team’s results, published in the scientific journal Analytical and Bioanalytical Chemistry, describe a mathematical technique for perceiving comparatively faint signals in diagnostic test data that indicate the presence of the virus. These signals can escape detection when the number of viral particles found in a patient’s nasal swab test sample is low. The team’s method helps a modest signal stand out more clearly.

“Applying our technique could make the swab test up to 10 times more sensitive,” said Paul Patrone, a NIST physicist and a co-author on the team’s paper. “It could potentially spot more people who are carrying the virus but whose viral count is too low for the current test to give a positive result.”

The researchers’ findings prove that the data from a positive test, when expressed in graphical form, takes on a recognizable shape that is always the same. Just as a fingerprint identifies a person, the shape is unique to this type of test. Only the shape’s position, and importantly, its size, differ when graphed, varying with the quantity of viral particles that exist in the sample.

While it was known previously that the shape’s position could vary, the team learned that its size can vary as well. Reprogramming test equipment to recognize this shape, regardless of size or location, is the key to improving test sensitivity.

The swab test employs a lab technique called quantitative polymerase chain reaction, or qPCR, to detect the genetic material carried