Saliva-Based Rapid Strep Testing

Burst Diagnostics is developing a first-in-class rapid antigen test for ultrasensitive and saliva-based
detection of Strep A.

Group A Streptococcus, commonly known as strep throat, accounts for 20-40% of pharyngitis cases in children.

Strep throat is a leading cause of urgent care and primary care visits, especially among children, with over 24 million strep tests performed annually in the U.S.

Despite the prevalence, current testing methods are insensitive, uncomfortable, or prohibitively expensive. As a result, many providers are forced to rely on incomplete information, leading to unnecessary antibiotic prescriptions, antimicrobial resistance, and gut health concerns in pediatric patients.

As many as

10,000,000

unnecessary antibiotic prescriptions could be provided to children each year for respiratory conditions.

Current Standard of Care

To determine if an individual has strep throat, providers perform a physical evaluation and score the patient’s symptoms. For moderate and severe symptoms, the treatment protocol is relatively straightforward.

If the symptoms are mild or not as clear, however, doctors collect two swabs, one for a rapid strep test (RST) and a second for a culture test.

Even when RSTs come back negative, many physicians initiate an antibiotic treatment while waiting for culture results.

Why is this happening?

  • Tradeoff Between Cost and Accuracy

    Current rapid strep tests fall into two categories: low-cost tests that lack sensitivity and high-cost tests that are more accurate but often go unreimbursed. Providers must choose between affordability and diagnostic confidence, leading to precautionary antibiotic use or backup testing that delays results.

  • Uncomfortable & Inaccurate Sampling

    Throat swabs, the current standard for strep testing, are uncomfortable, especially for children. Providers report gagging, vomiting, and difficulty getting a proper sample. Poor swabbing technique leads to false negative results, and the experience is painful for patients and clinicians alike.

  • Reliance on Confirmatory Lab Testing

    When rapid test results are negative or inconclusive, providers rely on culture testing, the clinical gold standard. Cultures require shipment to an external lab which can take 48 hours or more to return results. This delay can disrupt timely treatment and lead to antibiotic overprescription.

That’s where Burst comes in.

At Burst Diagnostics, we’re building a next-generation strep test that delivers accuracy, speed, affordability, and comfort without compromise.

Our CaDI platform provides lab-quality results in under 10 minutes in a cost-effective, user-friendly format built for clinical use. Preliminary data has shown 100x improved sensitivity compared to existing rapid antigen strep tests.

CaDI also replaces the traditional throat swab with a saliva swab, improving upon both patient comfort and sample consistency, especially in children.

Our CaDI strep test was awarded NIH grant support to conduct usability testing and pilot clinical studies for our saliva-based Strep A test, in collaboration with ACME POCT, Emory University, Children’s Healthcare of Atlanta, and Georgia Tech.

By delivering accuracy without tradeoffs, CaDI is redefining what’s possible for point-of-care strep diagnostics.

References

(1)Cohen, J.F. et al. (2016) ‘Rapid antigen detection test for Group A streptococcus in children with pharyngitis’, Cochrane Database of Systematic Reviews, 2016(7). doi:10.1002/14651858.cd010502.pub2.

(2) URGENT CARE INDUSTRY WHITE PAPER The Essential Nature of Urgent Care in the Healthcare Ecosystem Post-COVID-19 (2023) Urgent Care Association. Available at: https://urgentcareassociation.org/wp-content/uploads/2023-Urgent-Care-Industry-White-Paper.pdf (Accessed: 29 April 2025).

(3) Analysis of ICD-10 & CPT coding trends (2018) Experity. Available at: https://www.experityhealth.com/research/icd-10-cpt-and-e-m-coding-trends/ (Accessed: 29 April 2025).

(4) Hayes, R. et al. (2019) ‘Antibiotic prescriptions for upper respiratory infections in a pediatric office versus an Urgent Care Center’, Global Pediatric Health, 6. doi:10.1177/2333794x19835632.

(5) Choby, B. (2009) ‘Diagnosis and Treatment of Streptococcal Pharyngitis’, American Family Physician, 79(5), pp. 383–390.