Plate Contamination or Optical Interference (ELISA (High Background))

Question

Accepted Answer

Random high background in specific wells or patterns. Fingerprints, dust, or residue visible on plate bottom. Erratic readings not following expected pattern. Common causes: 1) Fingerprints or oils on optical reading surface of plate 2) Dust or particulates on plate bottom interfering with detection 3) Cross-contamination between wells during pipetting 4) Residual cleaning agents or detergents in wells Solutions: 1) Clean plate bottom with lint-free wipe and 70% ethanol following manufacturer instructions 2) Handle plates by edges only, avoid touching optical surfaces 3) Use new plate if contamination persists after cleaning 4) Change pipette tips between wells to prevent cross-contamination 5) Ensure plates are completely dry before reading