A PCR-free SARS-CoV-2 RNA detection test

Team Lead: Bhushan Toley
Email: bhushan@iisc.ac.in

Currently, the most effective method available to us to diagnose COVID-19 is the reverse transcriptase-polymerase chain reaction (RT-PCR), which directly detects the viral RNA. Although RT-PCR testing has been scaled up appreciably over the past few months, testing is still limited to designated central laboratories having expensive thermal cyclers. On the other hand, rapid antigen and antibody tests have been developed that enable testing for the virus at the point-of-care, but their accuracy does not match that of RNA-based tests.

Our lab is developing an RNA-based test for COVID-19 that does not rely on PCR, thus obviating the need for expensive thermal cyclers. Instead, we are developing a test that relies on isothermal nucleic acid amplification of nucleic acids, which can be conducted at a constant temperature in very low-cost heating instruments. The result of the test is readable by naked eye. The envisioned accuracy (sensitivity and specificity) of this test will match that of RT-PCR and the test may be conducted at various points-of-entries, e.g. airports, check posts etc.

We are leveraging our previous experience with developing paper-based analytical devices and PCR-free tuberculosis nucleic acid amplification tests for this work.


  • Team lead: Bhushan J. Toley, Assistant Professor, Dept. of Chemical Engineering
  • Primary developers: Vishnu Kumar, Venkata Subramanian Ramesan, Suraj Kumar Joshi
  • Support: Navjot Kaur, Priyanka Agarwal


  • Kaur, N., Michael, J. S. & Toley, B. J. A modular paper-and-plastic device for tuberculosis nucleic acid amplification testing in limited-resource settings. 1–12 (2019). doi:10.1038/s41598-019-51873-8
  • Kaur, N. & Toley, B. J. Paper-based nucleic acid amplification tests for point-of-care diagnostics. Analyst 143, 2213–2234 (2018).
  • Kaur, N., Thota, N. & Toley, B. A Stoichiometric and Pseudo Kinetic Model of Loop Mediated Isothermal Amplification. ChemRxiv (2020). doi:10.26434/chemrxiv.12540233.v1

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