While the field of preventive health through wearables is in constant progression, no product on the market allows yet to continuously, non-invasively and non-intrusively track a panel of biomarkers to provide monitoring in real time. This is true for biomarkers in general, and even more in the case for cytokines, which are notoriously hard to detect. Saliva, urine and exhaled breath are other types of biofluids that can be commonly sampled by medical practitioners. Collection of saliva with a swab is indeed very convenient: the biofluids is abundant and easily accessible, but it is not practical for continuous testing. Furthermore, saliva viscosity varies enormously, making the development of a standard solution fairly challenging. Urine is more widely used for tests, especially for tests related to drugs of abuse, hormones and pregnancy tests. Exhaled breath offers interesting opportunities in the space of breath volatile organic compounds for respiratory conditions, although like saliva and urine, it is fairly inadequate for continuous testing. Tear fluids and sweat have recently gained much interest as highly promising biofluid alternatives to blood. These “emerging biofluids” were previously deemed too challenging to access, but major progress in miniaturization of engineering solutions have suddenly put them in the spotlight. Tear fluid, for example, has emerged as an interesting candidate for continuous glucose monitoring, and research groups are working on enhancing contact lenses in varying stages of clinical validation. However, while eye tears can be accessed almost continuously, they are mixed with a lipid and mucous layer, and user acceptance for a rather invasive solution in a highly sensitive and infection-prone area of the body has yet to be proven. ISF by contrast appears much better suited for continuous collection.