Inadequate Washing Between Assay Steps (ELISA (High Background))

Question

Accepted Answer

High background with retained signal in negative controls. Edge wells may show higher background than center wells. Residual reagents visible in wells. Common causes: 1) Insufficient number of wash cycles between incubation steps 2) Wash buffer contact time too short (incomplete removal) 3) Incomplete aspiration leaving residual unbound antibodies 4) Wash buffer volume inadequate to fully rinse wells Solutions: 1) Increase number of wash cycles (minimum 3-5 washes per step) 2) Extend washing time, allow buffer to sit 30-60 seconds per wash 3) Ensure complete aspiration or decanting between washes 4) Use adequate wash buffer volume (typically 300-400 µL per well for 96-well plate) 5) Tap plate firmly on absorbent paper to remove residual buffer