Smell loss is an early indicator of infectious and neurodegenerative disorders. In COVID-19, for example, objective smell loss may occur in >90% of patients. Though molecular (PCR) tests are effective in diagnosing SARS-CoV-2 infection, with moderate sensitivity and high specificity, they typically are costly (>$50), with long turnaround times (up to 5-7 days) and have not been as effective in controlling asymptomatic spread. The Aromha Smell Test complements molecular tests with high sensitivity and negative predictive value and can be scaled quickly to provide an important new tool to prevent community spread of COVID, with an at-home, non-invasive, safe, and cost-effective screening test that provides instantaneous results. This platform technology, developed based on 20 years of olfactory research at Harvard, can also be utilized to provide an early signal and improve care in critical neurodegenerative diseases such as Alzheimer's, Parkinson's Disease, and Traumatic Brain Injury.