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)
Tissue Imaging (Autofluorescence) moderate

Inconsistent Antigen Retrieval Results

Antigen retrieval (AR) performance varies unpredictably across sections and targets. Harsh AR needed to recover signal suggests overfixation. Epitope accessibility inconsistent even with standardized protocols.

💡 5 causes ✓ 6 fixes
Tissue Imaging (Autofluorescence) severe

True Signal Loss After Autofluorescence Quenching

Signal drops or disappears after applying Sudan Black B or other quenching treatments. Target staining reduced along with background. Tissue morphology may be affected.

💡 5 causes ✓ 6 fixes
Tissue Imaging (Autofluorescence) critical

Improper Channel and Fluorophore Assignment

Everything glows in green/yellow channels. Dim targets overwhelmed by autofluorescence. Blue and green channels showing high background across tissue types. Spectral crowding and bleed-through between channels.

💡 5 causes ✓ 6 fixes
Tissue Imaging (Autofluorescence) severe

Melanin Pigment Interference

Unpredictable autofluorescence and signal quenching in pigmented tissues such as skin and retina. Melanin both autofluoresces and quenches true signal in unpredictable patterns.

💡 4 causes ✓ 5 fixes
Tissue Imaging (Autofluorescence) moderate

Metabolic Cofactor Autofluorescence

Endogenous fluorescence from NADH, FAD, and other metabolic cofactors in high-metabolism tissues such as kidney, liver, pancreas, and spleen. Complex extracellular matrices contribute additional background.

💡 4 causes ✓ 5 fixes
Tissue Imaging (Autofluorescence) moderate

Fixation-Induced Aldehyde Fluorescence

Strong blue-green autofluorescence haze in formalin or glutaraldehyde-fixed tissues. Background increases with fixation duration and disproportionately contaminates lower-wavelength channels. Amplified by paraffin embedding and overfixation.

💡 5 causes ✓ 6 fixes
Tissue Imaging (Autofluorescence) severe

Age-Related Lipofuscin Accumulation

Exceptionally broad excitation and emission spectra affecting multiple channels in aged tissues such as brain, heart, skeletal muscle, and retina. Age-dependent lysosomal pigment cannot be confined to single channel.

💡 4 causes ✓ 5 fixes
Tissue Imaging (Autofluorescence) severe

Collagen and Elastin Structural Protein Autofluorescence

Strong broad-spectrum autofluorescence in collagen and elastin-rich tissues including skin, lung, vessel walls, and fibrotic tissue. Emission persists through fixation and processing.

💡 4 causes ✓ 5 fixes
Tissue Imaging (Autofluorescence) severe

Red Blood Cell and Heme-Related Autofluorescence

Strong autofluorescence across multiple channels in blood-rich tissues such as spleen, liver, brain, bone marrow, and vascularized tumors. Heme and porphyrins dominate signal especially when tissue is not thoroughly perfused.

💡 4 causes ✓ 5 fixes