Antibiotics (Abx) are the world's most misused drugs. Antibiotics misuse occurs when the drug is administered in case of a non-bacterial infection (such as a viral infection) for which it is ineffective. Overall, it is estimated that 40-70% of the worldwide Abx courses are mis-prescribed. The financial and health consequences of Abx over-prescription include the direct cost of the drugs, as well as the indirect costs of their side effects, which are estimated at >$15 billion annually. Furthermore, over-prescription directly causes the emergence of Abx-resistant strains of bacteria, which are recognized as one of the major threats to public health today. This generates an immediate need for reliable diagnostics to assist physicians in correct Abx prescription, especially at the point-of-care (POC) where most Abx are prescribed. Accordingly, some aspects of the present invention provide methods using biomarkers for rapidly detecting the source of infection and administrating the appropriate treatment.