title: The accuracy of measurement required for acceptable estimation of non-steady rates of appearance and disappearance by the tracer method using a two-compartment model.
abstract: The two-compartment method for measuring non-steady-state glucose turnover rates was examined by computer simulation and by in vivo experiment. Given perfectly accurate input data, the simulations showed that the calculated turnover rates agreed closely with the true answer (agreement was not perfect however, because of the necessity for interpolation between the observed points). Contaminating the input data with a single erroneous observation of either tracee or tracer concentration produced large, spurious oscillations in the calculated turnover rates, the duration of which was inversely proportional to the frequency with which the infused compartment was sampled. Contaminating the perfect input data with observational noise of a magnitude approximately equal to the known measurement uncertainties showed that the calculations were very sensitive to noise and this was verified by in vivo experiment. It is concluded that non-steady-state glucose kinetics can be successfully measured by the two-compartment technique, but that measurements to an accuracy of at least 1% (coefficient of variation) are required.
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000378:metabolism*; D001825:Body Fluid Compartments; D003201:Computers; D007700:Kinetics; D008433:Mathematics; D008954:Models, Biological; D011849:Radioactive Tracers; D011868:Radioisotopes; D013552:Swine; D014316:Tritium
chemical_list: D001786:Blood Glucose; D011849:Radioactive Tracers; D011868:Radioisotopes; D014316:Tritium