Better reference would be an ELISA test (which is actually brought up as the reference in the paper)[^1]. That seems to also run about $5 per kit per antigen[^2

Better reference would be an ELISA test (which is actually brought up as the reference in the paper)[^1]. That seems to also run about $5 per kit per antigen[^2]. However this device seems to only require the test strip to be replaced, whereas you can only run ELISA once per strip/reagents. Also note that ELISA is harder to run so you have personnel costs and also this device claims higher sensitivity. [^1]: https://pubs.aip.org/avs/jvb/article/42/2/023202/3262988/High-sensitivity-saliva-based-biosensor-in https://pubs.aip.org/avs/jvb/article/42/2/023202/3262988/Hig... [^2]: https://www.thermofisher.com/elisa/product/ErbB2-HER2-Human-ELISA-Kit/EHERBB2 https://www.thermofisher.com/elisa/product/ErbB2-HER2-Human-..., note that I didn't shop around for necessarily the best prices.