Intern analytisk præcision skal være under + / - 0, 3 ‰ δ13C for 20 gentagne analyser af samme referencegasprøve og skal forblive inden for 3SD' er af gennemsnittet for UBT- analysen.
Internal analytical precision must be less than + 0.3 ‰ δ 13C for 20 replicate analyses of the same reference gas sample and remain within 23SD’ s of the mean for breath analyses.