Failure Case Library

Real lab failures, root causes, and fixes — curated and bilingually annotated by our team.

All Techniques (7) PCR (Sigma Guide) (12) End-point PCR Primers (9) Western Blot (9) Wound Healing Assay (5) Cell Culture (Contamination) (7) Lipid Transfection (8) CCK-8 Cell Viability Assay (5) Colony Formation Assay (10) Transfection (8) Nucleic Acid Quantification (9) Transfection (Co-transfection) (1) Protein Extraction (4) Plasmid Construction (Double Digest) (1) Sanger Sequencing (2) Plasmid Construction (1) qPCR (RT-qPCR) (5) Transwell Migration / Invasion Assay (5) Immunohistochemistry (IHC) (6) PCR (Polymerase Chain Reaction) (26) Restriction Enzyme Digest (13) DNA Cleanup & Plasmid Purification (7) RNA Cleanup (4) NGS Library Preparation (NEBNext Ultra II) (7) HMW DNA Extraction (Monarch) (7) LAMP (Loop-mediated Isothermal Amplification) (7) RNA Depletion for RNA-seq (7) Bacterial rRNA Depletion (4) Cell-free DNA Extraction (8) ELISA (Competitive) (18) ELISA (Signal Problems) (11) ELISA (High Background) (8) ELISA (Inconsistent Results / High CV) (6) ELISA (Standard Curve Fit Problems) (6) Western Blot (Weak / No Signal) (6) Western Blot (Detection Problems) (7) Western Blot (Bands at Wrong MW) (5) Western Blot (Misshapen / Uneven Bands) (5) Western Blot (Unexpected Multiple Bands) (7) Western Blot (Unusual Gel Band Appearance) (3) ChIP (High Background) (1) ChIP (Low Resolution with High Background) (6) ChIP (Low Signal) (8) ChIP (PCR Amplification Problems) (4) Immunohistochemistry (High Background) (9) Immunohistochemistry (No Staining) (9) Immunoprecipitation (High Antibody Elution) (1) Immunoprecipitation (High Background) (8) Immunoprecipitation (No Protein Detected) (5) Immunoprecipitation (Protein Obstruction) (1) ELISPOT (8) Tissue Imaging (Autofluorescence) (9) Flow Cytometry (Troubleshooting) (8) ELISA Development (9) Flow Cytometry (Autofluorescence) (7) Flow Cytometry (Compensation) (7) Flow Cytometry (Fc Blocking) (7) Flow Cytometry (Fixation & Permeabilization) (9) Flow Cytometry (Isotype Controls) (7) Flow Cytometry (Fixation Buffers) (7) Western Blot (CST Guide) (8) ChIP (CST Guide) (8) Immunoprecipitation (CST Guide) (14) Immunohistochemistry (CST Guide) (14) Flow Cytometry (CST Guide) (8) ELISA (R&D Guide) (10) ELISA (Sigma Guide) (6) Western Blot Immunodetection (19) IP-Western Blot (6) Flow Cytometry (Sample Considerations) (14) Flow Cytometry (Paraformaldehyde Fixation) (14) Western Blot (Sigma Protocol) (8) PCR / RT-PCR Amplification Problems (5) Cell Culture (Cell Death) (8) Cell Culture (Precipitates) (6) PCR (Invitrogen Guide) (8) PCR / qPCR Plastics (9) Flow Cytometry (Controls) (8) Plasmid Mini-prep (1) Transfection (siRNA Knockdown) (1) Western Blot (Blue Background) (1)
Cell Culture (Contamination) moderate

Incubator-Associated Mold Contamination

Recurring fungal contamination in cultures after incubation. Multiple cultures affected over time. Visible mold growth may appear on incubator surfaces. Persistent contamination despite replacing affected cultures.

💡 6 causes ✓ 8 fixes
Cell Culture (Contamination) severe

Contamination from Aerosol Generation

Multiple cultures becoming contaminated simultaneously or in sequence. Contamination spreading despite apparently good technique. Cross-contamination between neighboring cultures.

💡 7 causes ✓ 9 fixes
Cell Culture (Contamination) moderate

Chemical Contamination from Residues

Poor cell growth, cell death, or altered cell behavior without visible microbial contamination. May include effects from free radicals, metal ions, disinfectant/detergent residues, or endotoxins persisting after bacterial contamination is cleared.

💡 6 causes ✓ 6 fixes
Cell Culture (Contamination) critical

Viral Contamination - Difficult to Detect

Unexplained cell detachment, poor cell health, or cell death. Non-cytopathic viruses may show no obvious signs. Cannot be detected by conventional light microscopy. May not present significant effects if virus is host/tissue-restricted.

💡 6 causes ✓ 7 fixes
Cell Culture (Contamination) severe

Fungal and Yeast Contamination

Visible turbidity and color change of medium. Fungal structures visible under standard light microscopy. Rapid onset similar to bacterial contamination. May include visible mold growth.

💡 6 causes ✓ 8 fixes
Cell Culture (Contamination) critical

Mycoplasma Contamination - Silent Growth Inhibitor

Slowed cell growth, altered cellular metabolism, chromosomal aberrations, and interference with cell attachment. No visible turbidity in medium. Difficult to detect by light microscopy due to small size (0.15-0.3 µm).

💡 6 causes ✓ 7 fixes
Cell Culture (Contamination) severe

Bacterial Contamination with Rapid Turbidity

Rapid-onset turbidity and color change of culture medium (when phenol red is present). Medium becomes cloudy and pH indicator changes color quickly.

💡 7 causes ✓ 9 fixes