Measurement of beta 2 microglobulin in dried urine spotted on filter paper by means of a forward sandwich enzyme-linked immunosorbent assay.

We devised a highly sensitive forward sandwich enzyme-linked immunosorbent assay (ELISA) for estimation of the beta 2-microglobulin concentration in dried urine spotted on filter paper. This method is suitable for mass screening because of the good reproducibility, satisfactory stability, low operation cost and easy sample collection. However, preliminary studies using our new method for detecting renal diseases in the Tokyo infant population did not produce good results. The high cut-off value may have been the main reason. To make this ELISA more suitable for mass screening, we plan to reduce the cut-off value, test older children and improve the extraction step.