NOWDiagnostics’ First to Know has FDA De Novo marketing authorization as a new test for syphilis. The at-home product needs only a single drop of blood to test for this sexually transmitted infection.

By Frank VinluanSyphilis testing typically requires obtaining a blood sample and sending it to a lab. The wait for results ranges from hours to days. The FDA has authorized a new at-home syphilis test, a NOWDiagnostics product that yields results within 15 minutes.
The FDA said Friday that its marketing authorization for the NOWDiagnostics test makes the kit the first at-home, over-the-counter test for syphilis. Springdale, Arkansas-based NOWDiagnostics, or NOWDx, will market its new syphilis test as First-to-Know.
Syphilis is caused by a bacterium, Treponema pallidum. It’s treatable with antibiotics, such as penicillin. Untreated, syphilis infection can damage the heart and the brain. This infection can also cause blindness, deafness, and paralysis. Reports of this sexually transmitted infection have been rising. According to the Centers for Disease Control and Prevention, cases increased 80% from 2018 to 2022, continuing an upward trend going back decades.
First to Know tests a single drop of blood to detect Treponema pallidum antibodies. The FDA decision for this test is based on a clinical study that enrolled 1,270 participants and compared results from First to Know against three FDA-cleared laboratory tests. Data show that the negative percent agreement was 99.5%, which means the test correctly identified 99.5% of negative specimens. The positive percent agreement, or the correct identification of positive specimens, was 93.4%.
The FDA cautions that the risks of First to Know are mainly the possibility of false positive or false negative results, the same risk that comes with other diagnostic tests. The agency notes that positive results from this test alone do not constitute a diagnosis of syphilis infection and such results should be followed by additional testing to confirm a syphilis diagnosis.
“There is a critical need to increase public awareness about the seriousness of untreated syphilis, especially in underserved and marginalized populations,” Dr. Gregory Bledsoe, former surgeon general for Arkansas, said in NOWDx’s announcement of the regulatory decision. “An in-home test like this has the potential to greatly impact public health by improving access to timely detection and treatment.”
NOWDx develops over-the-counter and point-of-care diagnostic tests. The company says its technology allows virtually any immunological assay to be performed in a single step using a small amount of blood. The company is also developing tests that can analyze samples of saliva. Besides First to Know, the company sells blood tests for pregnancy and Covid-19. It says its pipeline has more than 30 tests in development.
The FDA said it reviewed First to Know under the De Novo premarket review pathway for new devices that have low-to-moderate risk. Marketing authorization of First to Know creates a new regulatory classification that establishes this test as a predicate device. Future tests of the same type and same intended use can be compared to First to Know under review through the FDA’s 510(k) pathway.
NowDx’s First to Know does not require a prescription. The company expects this new syphilis test will become available at retail locations and online later this year. Last month, the company closed $22.5 million in new funding to finance commercialization of First to Know. The Series B round was led by DigitalDx Ventures and included participation from Labcorp Venture Fund and Kompass Kapital Management.
Illustration: Christoph Burgstedt/Science Photo Library, via Getty Images