Abstract: A method of indicating the presence of a bacterial infection in a biological sample is provided. The method detects a marker for infection by providing a device, the device including a biosensor, an interaction arising between the biosensor and the marker when the marker is present in the biological sample. Contacting at least a part of the biological sample with the biosensor of the device, therefore, provides analysis of the biological sample with respect to the marker by detecting for the interaction between the biosensor and the marker. A preferred marker is the enzyme amylase.