Israeli Startup Launches World’s First Saliva-Based Pregnancy Test

Perhaps the only positive thing about the COVID-19 pandemic is how it has accelerated development of rapid, point-of-care diagnostics, not just in the US but around the world. One potential game changer may revolutionize the kind of home test women who miss a period use to determine if they are pregnant. Using COVID-19 detection technology to fertilize an idea originating before the pandemic, Israeli medical start-up Salignostics is getting ready to launch the world’s first pregnancy test based on saliva samples.

Saliva-Based Pregnancy Diagnostics

In addition to being easy to detect and store, saliva is known to contain biomarkers that can be used for early detection of different diseases and medical conditions. The presence of multiple biomarkers makes saliva ideal for development of simple, noninvasive multiplexed assays that can be performed quickly at the point of care.

One example of a useful biomarker found in saliva is beta-human chorionic gonadotropin (β-hCG) found in plasma and urine, measurement of which can be used to detect levels of hormones associated with pregnancy. β-hCG levels in saliva are usually detectable at about three to four weeks into pregnancy and continue to increase as the pregnancy continues. But despite its potential diagnostic advantages, there have been only a few studies evaluating the role of saliva as a noninvasive, rapid, and more acceptable biofluid for pregnancy detection.

The GMIT Study

One study supporting the viability of using β-hCG levels in saliva to detect pregnancy was published in the journal Gynecology and Minimally Invasive Therapy in June 2019. The authors evaluated 35 women visiting a gynecology clinic for confirmation of pregnancy with a history of a missed menstrual cycle of no more than four weeks. Since there was no working home-based pregnancy detection kit, they used a kit designed for urinary β-hCG detection with 20 mIU specification to measure salivary β-hCG. A routine test that was prescribed for the patient such as laboratory-based urine β-hCG and/or ultrasound examination, was used to confirm pregnancy and for correlation with the saliva-based result.

All of the participants evaluated were in the age group 21 to 27 years of age, with 77 percent of patients between ages 23 and 26. About 43 percent of the participants had a history of missed period of less than or equal to 10 days, 49 percent between 11 and 15 days, and 9 percent more than 15 and 30 days.

Results of Salivary hCG Test

Confirmation of presence of pregnancy was obtained in 23 percent of participants by an ultrasound and 77 percent of participants by laboratory-based urine β-hCG level. Approximately 74 percent of participants with a confirmed pregnancy showed a positive result, of which 43 percent showed a dark band and 31 percent a light band. The researchers noted a negative result in 26 percent of participants. Of the nine subjects who showed a negative result, eight showed a positive confirmation with a urine test and one was confirmed negative on further evaluation.

Overall, study, salivary β-hCG estimations showed a 77 percent accuracy and 23 percent false-negative results. The authors surmised that accuracy might have been even better had they been able to use a home-based kit designed for pregnancy detection rather than one for urinary β-hCG detection.

“Though this was a pilot study and the kit used was a commercially available kit meant for urinary hCG, strong positive data obtained is encouraging and opens new avenues towards development of new saliva based diagnostic kits using salivary hCG as a diagnostic bio fluid for early detection of pregnancy,” the authors concluded. “With the findings obtained from our study we could positively affirm that Salivary hCG can be used as a potential, user friendly, more acceptable home based biomarker for early detection of pregnancy.”

The New Saliva-Based Pregnancy Test

Perhaps encouraged by the GMIT study, Jerusalem-based Salignostics set out to use its proprietary saliva-based hormone detection technology to develop a home test for early pregnancy detection. Like so many other companies did when the pandemic arrived, Salignostics shelved its plans to concentrate on COVID-19 testing. But a funny thing happened along the way. In developing its SaliCov rapid antigen test for COVID-19, which has received CE Marking from the European Union (EU) and is now widely used across Europe and Africa, Salignostics uncovered the missing piece they needed to bring the pregnancy assay to fruition.

The company reports that its resulting SaliStick test product has 95 percent sensitivity when women use it after they have missed a period. The company has successfully completed clinical trials in Israel on more than 300 women—both pregnant and non-pregnant—and has begun the process of applying for CE Marking and US Food and Drug Administration (FDA) approval. If it all works out, the company plans call for a commercial launch early in 2022.

Takeaway

The development of a better home pregnancy test that eliminates a woman’s need to pee on a stick may prove to be one of the unexpected consequences of the pandemic. Put into a broader perspective, the conception and birth of the SaliStick for saliva-based early pregnancy detection is an example of how the diagnostics and technology developed in response to the global health emergency may offer solutions to a wide range of medical challenges that have existed long before the coronavirus.