Precision diagnostics relies on omic analysis by mass spectrometry to overcome the limitation in accuracy by an individual biomarker, due to the complex nature of diseases. Recent development in nanotechnology markedly enhanced sample treatment and detection efficiency of this method. Herein, we foresee a coming era of precision diagnostics based on nano-assisted mass spectrometry. Some important progress in the field includes detection of (1) nucleic acids for genetic analysis; (2) proteins/peptides for proteomic analysis; and (3) small molecules for metabolic analysis. We anticipate that this review will be a reminder for both young and experienced researchers about the future of diagnostics and call for attention worldwide.