Failure Case Library

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

All Techniques (6) 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)
ChIP (Low Resolution with High Background) severe

Poor Chromatin Quality from Crosslinking or Fragmentation Issues

ChIP-seq shows high background noise with poorly defined peaks. DNA fragment size distribution is inconsistent, resulting in low resolution across genomic regions.

💡 4 causes ✓ 5 fixes
ChIP (Low Resolution with High Background) severe

Poor Library Quality from Overamplification or Contamination

ChIP-seq data shows elevated background noise, high duplication rates, and presence of nonspecific fragments. Peak resolution is reduced with diffuse signal patterns.

💡 4 causes ✓ 5 fixes
ChIP (Low Resolution with High Background) severe

DNA Fragment Size Too Large for Resolution

ChIP-seq peaks are broad and poorly defined, with low spatial resolution for pinpointing binding sites. Background signal is elevated across large genomic regions.

💡 4 causes ✓ 5 fixes
ChIP (Low Resolution with High Background) severe

Low Enrichment Due to Insufficient Starting Material

ChIP-seq exhibits low resolution with high background across large genomic regions. Signal-to-noise ratio is poor, with diffuse peaks and elevated baseline signal throughout the genome.

💡 4 causes ✓ 4 fixes
ChIP (Low Resolution with High Background) moderate

Insufficient Sequencing Depth for Target Type

ChIP-seq produces broad, noisy peaks with poor statistical confidence. Peaks are difficult to call reliably, especially for diffuse histone marks or low-abundance transcription factors.

💡 4 causes ✓ 5 fixes
ChIP (Low Resolution with High Background) critical

Antibody Lacks Specificity or ChIP Validation

ChIP-seq generates high background signal across the genome with poor enrichment at expected binding sites. Signal-to-noise ratio is low, and peaks are difficult to distinguish from background.

💡 4 causes ✓ 5 fixes