Clinical mass spectrometry is not a novel concept in Japan. Despite national funding for the use of mass spectrometry in newborn screening, and as tools for use in forensic medicine, toxicology and more, it has limited use in routine testing regimes in clinical laboratories. In his talk at the Re-imagining Mass Spectrometry Symposium, Prof Fumio Nomura, Visiting Professor in the Division of Clinical Genetics, Chiba University Japan, spells out the challenges commonly associated with the use of clinical mass spectrometry, and encourages the adoption of it by weighing its considerable advantages over immunoassays.