The albumin-functionality-test uses electron spin resonance spectroscopy (ESR) to estimate the functionality of the transport protein albumin in human serum. It is based on a comparison of three different serum albumin solutions with increasing concentrations of a spin-labelled fatty acid 16-DOXYL-stearic acid (16-DSA) and ethanol, which simulate binding, transport and release conditions in vitro.

By adding a spin-labelled fatty acid the three binding sites with high as well as four with low affinity could be investigated.

By simulating the ESR spectra binding constants, binding capacities and biophysical parameters of both binding site types in the three different serum-ethanol-fatty acid solutions can be estimated.

By means of these parameters the transport properties can be calculated by interrelating individual values of the three different serum-ethanol-fatty acid solutions with each other.