Conventional immunoassay tests are analog in nature, confirming the diagnosis of disease (Yes/No) or the presence of a foreign substance (Yes/No).  Function Immunoassay Technology (FIT) diverges from this convention by designing tests to evaluate and gauge the functional performance of an organ or organ system by sequential measurements of exogenously administered compound thereby allowing the calculation of a kinetic parameter.  FIT thus combines the techniques of immunoassay as a readout system with the concept of pharmacokinetics to measure the kinetic behavior of an administrated compound or set of compounds.  Limits on the rate of clearance or accumulation of the compound as measured in biological material provide the input parameters to calculate a functional index for the organ-of-interest.

BioPAL has applied FIT to develop methods to measure glomerular filtration rate (FIT-GFR) and effective renal plasma flow (FIT-RPF).  FIT is a patent pending technology and additional FIT-based tests are under development.