A rapid digital self-test for multiple infections without amplification, reagents or enzymes.

New graphene sensor technology commercialized at Purdue University is intended to disrupt PCR industry for multiple infections

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How is Check4™ different from other COVID tests?

Check4™ — developed by IdentifySensors Biologics and commercialized at Purdue University, is a rapid digital diagnostic platform as accurate as a PCR test. This digital platform uses no enzymes, reagents or amplification. 

Check4™ uses newly developed digital graphene sensors for fast, highly accurate results.  

The Check4 device connects wirelessly to  smartphones to display results in minutes, anywhere, any time. The reusable reader is intended to cost about $160. Each test cartridge is intended to cost about $60.

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A highly accurate and affordable over-the-counter self-test that uses saliva and digital sensors.


Check4™ — a rapid self-test intended to be as accurate as a PCR test in minutes without amplification, reagents or lab work. A graphene-based sensor interacts with saliva to produce a distinguishable electronic signal for positive or negative results with accuracy that rivals PCR tests. Results are displayed in minutes on a smartphone app and automatically notifies health authorities.


Check4™ is intended to meet the gold-standard in testing for viruses and bacteria. The test was commercialized at Purdue University by world-renowned scientists. It is intended to avoid the limitations of current molecular tests such as enzymatic reactions, amplification, sample preservation or sample transportation, which can introduce artifacts and raise the risk of false positives.


Check4™ is anticipated to cost significantly less than PCR tests. This approach avoids costly elements used by laboratory-based tests such as enzymes and reagents that are in short supply. It also eliminates the need for laboratory technicians, diagnostic machines and personal protective equipment.

Check4™ Features

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An over-the-counter saliva test intended to produce highly accurate results without a prescription or doctor’s visit.

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Intended to meet the gold standard of PCR testing, including asymptomatic infections that rapid antigen tests miss. 

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Frequent Testing

Small portable readers intend to enable frequent, inexpensive self-testing, anywhere, any time.

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Disposable cartridges are intended to cost less than $60 without a prescription.

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Tests are intended to be programmed to detect any specific pathogens, including MRSA, SARS, Influenza and HIV.

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Electronic signals are sent to a smartphone app to display test results within minutes.

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How does Check4™ work?

Consumers buy a small, simple device online or from a retail store and download the free smartphone app. The device includes a reusable reader that transmits data to a smartphone and a single-use sensor cartridge. A saliva sample is placed in the sensor cartridge and signals are sent to the reader for processing. Test results are transmitted to a smartphone app within minutes.

Results Appear in Minutes on Your Smartphone – anywhere, anytime:

  • Real-time test results can be monitored remotely
  • Highly accurate results in 5 minutes
  • No prescriptions
  • No amplification or reagents
  • No laboratories
  • No mailing in samples
  • No high costs