A mathematical model to predict the optimal test line location and sample volume for lateral flow immunoassays.

Lateral flow immunoassay (LFIA) platform is one of the most relevant technologies for screening and diagnosing clinical conditions. However due to low sensitivity and poor repeatability of the platform it has been used only for limited and non-critical tests. Mathematical models have been used to understand the principles of capillary flow and antibody antigen based immunoreactions in nitrocellulose membrane typically seen in LFIA. The model presented in this paper predicts the optimized location of test line on LFIA strip, sample volume and total reaction time that is needed to achieve the required sensitivity for different analytes on a case to case basis. The membrane properties like capillary flow time (s/cm), concentration and affinity constants of antibodies can be varied and the corresponding effect on strip design can be found. Hence this model can be used as a design tool to optimize the LFIA strip construction and reagent development processes.