Western Blot practical handbook
Western Blot protocol, troubleshooting and quantification guide
Find working conditions and common problems by experimental step, from sample preparation and SDS-PAGE through transfer, antibodies, detection and quantification.
From a blot to an interpretable result
An attractive band is only a starting point. Preserve evidence for these three questions before changing the experiment or calculating a result. The worked examples, equations and records help document that reasoning.
01 · Is the loading range usable?
Do not copy a mass without context. Separate lysate from purified protein, then compare target and reference responses across a loading series.
Compare sample inputs and worked loads →02 · Where did the failure start?
Use membrane staining, the post-transfer gel, positive controls and whole-blot patterns. Compare one clearly defined change in a round.
Plan a controlled transfer comparison →03 · Can the relative value be traced?
Keep the source image and regions, subtract local background by area and normalize each sample. Different exposures and technical repeats are not independent biological samples.
Recalculate relative signal from pixels →
Western Blot workflow
Choose the step you are working on. Each guide lists starting conditions, checks to make and signs that the method needs adjustment.
01
Sample preparation
Choose extraction for the target compartment, verify protein-assay compatibility and determine a usable sample input.
Open guide →
02
SDS-PAGE
Choose the gel system and separation range, then check lane shape and target-region resolution before transfer.
Open guide →
03
Transfer
Choose the transfer method and membrane, then confirm that the target-size region left the gel and remained on the membrane.
Open guide →
04
Blocking & antibodies
Use the antibody instructions to choose blocker and diluent, then adjust primary and secondary conditions separately.
Open guide →
05
Detection
Match the secondary conjugate, substrate or fluorophore to the imager and preserve an unsaturated source image.
Open guide →
06
Quantification
Confirm target and normalization signals are within a usable response range before calculating changes.
Open guide →
Something went wrong?
Start from the pattern on the whole membrane, then open the guide for that specific failure.
Common result patterns
Open troubleshooting guides →The whole blot is blank
Check acquisition and detection, transfer, the positive control and antibody pair.
Signal is present but faint
Separate low abundance from extraction, transfer, antibody and acquisition losses.
Uniform dark background
Check exposure and secondary antibody first, then washing and blocker/diluent compatibility.
Extra or unexpected bands
Check target biology, specificity controls, sample quality, loading and antibody conditions.
A lane forms a broad smear
Check degradation, viscosity, salts or detergents, overload and electrophoresis before antibody changes.
Uneven or patchy signal
Use the artifact position to check bubbles, coverage, contamination and the imaging surface.
The band is at the wrong size
Check isoforms, processing, modifications, reduction, aggregation, marker migration and specificity.
Laboratory tools and reference material
Planning guides, calculators, worksheets, diagnostic cases and source references are collected here.
Experimental planning
Confirm target biology, controls, extraction, membrane choice and the measurement plan before loading.
Open →
Loading controls
Validate housekeeping stability, signal range and total-protein alternatives before normalization.
Open →
Buffer recipes
Open common Western Blot buffer formulations with notes on where they may need adjustment.
Open →
Laboratory calculators
Calculate sample mixtures, antibody dilutions, TBST and other routine experimental volumes.
Open →
Experiment worksheets
Record actual conditions, raw-file locations and the next planned change in printable worksheets.
Open →
Diagnostic cases
Review common failure patterns, likely causes and experiments that help distinguish them.
Open →
References
Open the manufacturer protocols, methods papers and reporting guidance cited across the site.
Open →
About this handbook
The conditions on this site are starting points. Product instructions for the antibody, gel, membrane and equipment in use take priority, and important conditions should be checked in the actual experimental system.