Plate Contamination or Optical Interference

Symptom

Random high background in specific wells or patterns. Fingerprints, dust, or residue visible on plate bottom. Erratic readings not following expected pattern.

1. 1 Fingerprints or oils on optical reading surface of plate
2. 2 Dust or particulates on plate bottom interfering with detection
3. 3 Cross-contamination between wells during pipetting
4. 4 Residual cleaning agents or detergents in wells

1. 1 Clean plate bottom with lint-free wipe and 70% ethanol following manufacturer instructions
2. 2 Handle plates by edges only, avoid touching optical surfaces
3. 3 Use new plate if contamination persists after cleaning
4. 4 Change pipette tips between wells to prevent cross-contamination
5. 5 Ensure plates are completely dry before reading

Related Video (3)

Thermo Fisher Scientific ★ 75

How to Run an ELISA Assay – Invitrogen Kit Step-by-Step Tutorial

"Shows proper handling and plate-reading steps that minimize background issues from contamination on the optical surface."

Bilibili (China-Accessible Mirrors) ★ 72

How to Run an R&D Systems Quantikine ELISA

"Includes troubleshooting guidance relevant to erratic readings and high background in ELISA."

Bilibili (China-Accessible Mirrors) ★ 70

Thermo Fisher Microplate Reader Software Operation

"Demonstrates microplate reader operation, helping users avoid or detect optical interference from fingerprints or dust."