Oxygen-18 and carbon-13 isotopes in eCOand erythrocytes carbonic anhydrase activity of Finnish prediabetic population.

Complex human physiological processes create the stable isotopic composition of exhaled carbon dioxide (eCO), measurable with noninvasive breath tests. Recently, isotope-selective breath tests utilizing natural fluctuation inO/O isotope ratio in eCOhave been proposed for screening prediabetic (PD) individuals. It has been suggested thatO/O fractionation patterns reflect shifts in the activity of carbonic anhydrase (CA), an enzyme involved in the metabolic changes in the PD state.