Failure Case Library

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

All Techniques (9) 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)
Nucleic Acid Quantification moderate

Negative Fluorescence Values

Fluorescence reader displays negative values, which is physically impossible

💡 4 causes ✓ 5 fixes
Nucleic Acid Quantification moderate

Temperature-Related Reading Errors

Inconsistent or inaccurate readings caused by temperature variations in samples, standards, or reagents

💡 6 causes ✓ 8 fixes
Nucleic Acid Quantification severe

Fluorometer Screen Freezes or Won't Power On

Qubit Fluorometer screen becomes unresponsive, freezes, or instrument will not turn on

💡 4 causes ✓ 6 fixes
Nucleic Acid Quantification moderate

Unexpected or Incorrect Quantification Value

Qubit Fluorometer shows unexpected concentration values that do not match expected sample concentration

💡 10 causes ✓ 10 fixes
Nucleic Acid Quantification moderate

Fluorescence Value Decreasing Over Time

Qubit Fluorometer reading decreases when taking multiple measurements or reading after extended time

💡 5 causes ✓ 6 fixes
Nucleic Acid Quantification moderate

Qubit Value Lower Than UV Absorbance

Qubit Fluorometer quantification value is significantly lower than UV absorbance (NanoDrop) measurement for the same sample

💡 5 causes ✓ 5 fixes
Nucleic Acid Quantification minor

Sample Out of Range - Too Low

Qubit Fluorometer screen indicates samples are OUT OF RANGE (too low), sample fluorescence below lowest standard

💡 3 causes ✓ 5 fixes
Nucleic Acid Quantification minor

Sample Out of Range - Too High

Qubit Fluorometer screen indicates samples are OUT OF RANGE (too high), sample fluorescence exceeds highest standard

💡 3 causes ✓ 5 fixes
Nucleic Acid Quantification severe

Standards Incorrect Message on Qubit Fluorometer

Qubit Fluorometer displays 『Standards Incorrect』 error message during calibration or measurement

💡 7 causes ✓ 6 fixes