Suhail approached researchers to help design a test and obtained a bio-ethical clearance for further study. The idea was to collect saliva and blood samples to find out if there was any correlation with the colour change—the question being, would protein levels in the blood show up in saliva. For the latter, he used a machine learning algorithm to establish a basic pattern. “What we figured is that the colour change is in proportion to the amount of salivary protein you have. High salivary protein turns the colour white rapidly. If it’s low, there’s no colour change. The paper device, dosed with amylose-iodine complex, will cost only Rs 2,” he explains.