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CCK-8 Cell Viability Assay severe

High background — control OD is abnormally elevated

Symptom
Even blank wells (medium + CCK-8, no cells) show high OD; control group reads abnormally high.
Common Causes
  1. 1 CCK-8 reagent was contaminated or degraded
  2. 2 Phenol red in culture medium interferes with reading
  3. 3 Reagent incubation time too long
  4. 4 Plate or tip contamination
  5. 5 Wrong wavelength or reader baseline drift
Solutions
  1. 1 Switch to a fresh batch of CCK-8 reagent
  2. 2 Use phenol-red-free culture medium
  3. 3 Cap incubation at 1 – 2 h
  4. 4 Use clean plates and tips
  5. 5 Always include blank wells (medium + CCK-8 only) and subtract their average
Related Video (2)
YouTube (Curated Tutorials) ★ 95
CCK-8 Operation Guide & Data Analysis
"Directly demonstrates CCK-8 operation, reagent handling, and data analysis—essential for understanding how contamination/degradation manifests in control wells"
YouTube (Curated Tutorials) ★ 82
Cell Counting Kit-8 (CCK-8) Assay Principle
"Explains CCK-8 assay principle and kit usage, helping researcher recognize normal vs. abnormal background signals and reagent quality indicators"
Source: xiaohongshu.com ↗
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