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)
Flow Cytometry (Autofluorescence) severe

High Background Signal from Autofluorescent Cell Types

Elevated background fluorescence intensity across multiple channels, particularly affecting green (FITC) and orange (PE) channels. Difficult to distinguish specific antibody staining from background noise.

💡 5 causes ✓ 5 fixes
Flow Cytometry (Autofluorescence) severe

Aldehyde-Based Fixation Amplifying Autofluorescence

Fixed cell samples exhibit dramatically elevated autofluorescence compared to live cells, particularly in green and UV channels. Background signal increases after fixation protocol, reducing signal-to-noise ratio.

💡 4 causes ✓ 5 fixes
Flow Cytometry (Autofluorescence) critical

Excessive Autofluorescence in Solid Tissue Samples

Solid tissue samples display much higher autofluorescence than PBMCs across multiple channels. Tissue-derived cells show elevated background due to structural proteins, extracellular matrix components, and pigments.

💡 5 causes ✓ 5 fixes
Flow Cytometry (Autofluorescence) severe

Autofluorescence Interfering with Viability Dye Detection

Dead cell discrimination becomes unreliable as autofluorescence overlaps with viability dye emission spectra. False positive or false negative viability calls occur, particularly with green or orange viability dyes.

💡 4 causes ✓ 5 fixes
Flow Cytometry (Autofluorescence) moderate

Autofluorescence Complicating Cell Population Gating Strategy

Difficult to establish clear gates between positive and negative populations. Autofluorescent cells appear in unexpected regions of scatter plots, creating ambiguous boundaries and potential misidentification of cell populations.

💡 4 causes ✓ 5 fixes
Flow Cytometry (Autofluorescence) moderate

FITC Green Channel Highly Affected by Autofluorescence

FITC-conjugated antibodies show poor signal-to-noise ratio with elevated background in green channel. Blue laser (488 nm) excitation induces strong autofluorescence that directly overlaps with FITC emission spectrum.

💡 4 causes ✓ 5 fixes
Flow Cytometry (Autofluorescence) severe

Poor Resolution of Dim Markers Masked by Autofluorescence

Low-expression markers become indistinguishable from background. Positive and negative populations show poor separation, with dim fluorophores completely masked by cellular autofluorescence.

💡 4 causes ✓ 5 fixes