This method allows to evaluate the degradation of lactate during cellular respiration. During this metabolic process, carbon atoms of lactate can be transformed in carbon dioxide. For this purpose, the radioactive lactate is added to the cells and the amount of radioactive carbon dioxide liberated is monitored. The radioactive carbon dioxide generated during cellular respiration is released into the culture medium and it is further converted into gas through the addition of sulfuric acid to culture media. A piece of Whatman paper wet with phenyl-ethylamine-methanol is placed inside the petri dish to trap radioactive carbon dioxide whose production is then evaluated by scintillator counting.