Failure Case Library

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

All Techniques (8) 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-free DNA Extraction severe

Low cfDNA Yield Due to Improper Reagent Handling

Cell-free DNA extraction yields are lower than expected. This may manifest as insufficient DNA concentration measured by fluorometry or qPCR, preventing downstream analysis.

💡 4 causes ✓ 4 fixes
Cell-free DNA Extraction severe

Low cfDNA Recovery from Inadequate Bead Dispensing

DNA yield is consistently lower than expected across multiple extractions. The binding capacity appears reduced, with proportionally less DNA recovered relative to input sample volume.

💡 4 causes ✓ 4 fixes
Cell-free DNA Extraction severe

Poor cfDNA Binding from Inadequate Incubation

Cell-free DNA yield is suboptimal despite proper bead addition and reagent preparation. A significant portion of DNA may remain unbound in the supernatant during the binding step.

💡 4 causes ✓ 4 fixes
Cell-free DNA Extraction severe

Yield or Quality Issues from Incorrect Bead Drying

DNA yield is lower than expected, or downstream applications show inhibition. Under-dried beads may carry over ethanol or contaminants, while over-dried beads result in poor DNA release during elution.

💡 4 causes ✓ 4 fixes
Cell-free DNA Extraction severe

Low cfDNA Recovery from Incomplete Elution

Final DNA concentration is lower than expected despite successful binding and washing. A significant portion of DNA remains bound to the beads after the elution step.

💡 4 causes ✓ 4 fixes
Cell-free DNA Extraction moderate

DNA Loss from Bead Removal During Supernatant Transfer

Variable or reduced cfDNA yields across samples. Beads may be visible in wash supernatants or final eluate, or yield decreases progressively through the protocol.

💡 4 causes ✓ 5 fixes
Cell-free DNA Extraction moderate

Inherently Low cfDNA Yield from Sample Limitations

Consistently low cfDNA yields despite optimized extraction protocol. This pattern may occur across specific sample types or patient cohorts, reflecting biological rather than technical causes.

💡 4 causes ✓ 5 fixes
Cell-free DNA Extraction moderate

Magnetic Bead Contamination in Final cfDNA Eluate

Visible brown particles or turbidity in the final DNA eluate. This may cause downstream assay interference, optical measurement errors, or sequencing library preparation issues.

💡 4 causes ✓ 5 fixes