Failure Case Library

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

All Techniques (5) 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)
Western Blot (Misshapen / Uneven Bands) severe

Uneven Bands Due to Improper Gel Polymerization

Bands appear distorted, wonky, or uneven across lanes. In extreme cases, the same protein appears at different molecular weights in different lanes due to irregular gel matrix formation.

💡 4 causes ✓ 4 fixes
Western Blot (Misshapen / Uneven Bands) moderate

Band Warping from Well Overloading

Individual lanes show warped or distorted bands while adjacent lanes appear normal. Affected lanes may show smearing, broadening, or lateral spreading of protein bands.

💡 4 causes ✓ 4 fixes
Western Blot (Misshapen / Uneven Bands) moderate

Uneven Dye Front and Band Distortion

The dye front shows curving or warping during migration, resulting in uneven band patterns. Bands may appear tilted, curved, or compressed in certain regions of the gel.

💡 4 causes ✓ 4 fixes
Western Blot (Misshapen / Uneven Bands) moderate

Smile Effect on Western Blot Bands

Bands appear curved in a smile-shaped pattern across the gel, with edges migrating faster than the center. This distortion affects all lanes uniformly and compromises molecular weight estimation.

💡 4 causes ✓ 4 fixes
Western Blot (Misshapen / Uneven Bands) moderate

Streaking and Uneven Migration from Buffer Issues

Bands show streaking, smearing, or uneven migration patterns. Multiple bands may merge or appear poorly resolved with inconsistent migration across the gel.

💡 5 causes ✓ 5 fixes