There are multiple definitions:

1. immunofixation electrophoresis(English)

   • is able to characterize further or subtype M-proteins identified on SPEP. This technique takes advantage of Ab specificity for antigens and their ability to fix (e.g., immunoprecipitate) proteins in a gel matrix
   • SIFE, UPEP, UIFE, CSF, SPEP
   • Clinical chemistry
   • https://doi.org…15499-1.00022-3

2. inner filter effect(English)

   • used in in fluorescence spectroscopy
   • CDRS
   • Fluorescence, Spectroscopy
   • https://doi.org…rev.2019.100318