MicroRNAs or miRNAs are a form of small non-coding RNAs (ncRNAs) of 19-22 nucleotides in length in their mature form. miRNAs are transcribed in the nucleus of all cells from large precursors, many of which have several kilobases in length. Originally identified as intracellular modulators of protein synthesis via posttranscriptional gene silencing, more recently it has been found that miRNAs can travel in extracellular human fluids inside specialized vesicles known as exosomes. More interestingly, the miRNA content inside exosomes changes during pathological events. In the present review the authors analyze the literature about circulating miRNAs and their possible use as biomarkers. Furthermore, they explore their future in point-of-care (POC) diagnostics and provide an example of a portable POC apparatus useful in the detection of circulating miRNAs.