inglés al español Medicina Medicina: Instrumentos Immunoanalysis

I am translating a manual for an Enzyme Immunoassay (EIA). When describing the procedure to wash the microwells, the following sentence mentions the term 'background', which I do not fully grasp.

*Inadequate washing can cause excessive background in any EIA protocol.*

I guess it means that the residues create 'background noise'. Can anyone confirm or suggest the correct translation?

Kind regards,