<prompt> Radioisotopes are used in the following technique exceptMass spectroscopyRIAELISASequencing of nucleic acid  <response>: ELISA Enzyme linked Immunoabsorbent Assay is an enzyme-based immunoassay and does not use radioactive isotopes. A test similar to ELISA which uses radioactive isotope in place of the enzyme is known as Radioimmunoassay RIA. Nucleic acid sequencing, mass spectroscopy RIA are tested using radioisotopes. 