This thesis focuses on a multidisciplinary project to develop molecular methods for point-of-care (POC) diagnosis of infectious diseases. First, I describe an approach followed to develop a test that aims to discriminate bacterial infections from viral infections. The test is based on evidence that gene patterns detected in the blood of patients by isothermal amplification technologies used in conjunction with an electrochemical platform are specific enough to distinguish viral from bacterial infections. For the first time, a two-gene host blood RNA signature has been translated into a rapid (<25 minutes) and portable laboratory-on-a-chip platform, confirming that the approach holds significant potential for the development of quantitative diagnostics. 
Second, and in response to the rapid evolution of the COVID-19 pandemic and the need for rapid, sensitive and specific diagnostic methods, I focused on the translation of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) detection to the optimised lab-on-a-chip platform to deploy a test with minimal time, expertise and personnel requirements.
Third, a novel method that rapidly, efficiently and cost-effectively extracts nucleic acid (NAs) from a clinical sample has been developed and combined with an additional detection method based on colourimetric isothermal amplification providing a potential solution to detect pathogens within 30 minutes from sample to result. This thesis proposes novel approaches for the development of POC tests for disease diagnosis that may soon be considered in clinical practice.