Western Blot Quantifier

Source: https://github.com/aipoch/medical-research-skills

Western Blot Quantifier

Automatically identify Western Blot gel bands, perform densitometric analysis, and calculate normalized values relative to loading controls.

When to Use

• Use this skill when the task needs Automatically identify Western Blot gel bands, perform densitometric analysis, and calculate normalized values relative to loading controls.
• Use this skill for data analysis tasks that require explicit assumptions, bounded scope, and a reproducible output format.
• Use this skill when you need a documented fallback path for missing inputs, execution errors, or partial evidence.

Key Features

See ## Features above for related details.

• Scope-focused workflow aligned to: Automatically identify Western Blot gel bands, perform densitometric analysis, and calculate normalized values relative to loading controls.
• Packaged executable path(s): scripts/__init__.py plus 1 additional script(s).
• Structured execution path designed to keep outputs consistent and reviewable.

Dependencies

numpy>=1.21.0
opencv-python>=4.5.0
pandas>=1.3.0
matplotlib>=3.4.0
scipy>=1.7.0
scikit-image>=0.18.0

Example Usage

See ## Usage above for related details.

cd "20260318/scientific-skills/Data Analytics/western-blot-quantifier"
python -m py_compile scripts/main.py
python scripts/main.py --help

Example run plan:

1. Confirm the user input, output path, and any required config values.
2. Edit the in-file CONFIG block or documented parameters if the script uses fixed settings.
3. Run python scripts/main.py with the validated inputs.
4. Review the generated output and return the final artifact with any assumptions called out.

Implementation Details

See ## Workflow above for related details.

• Execution model: validate the request, choose the packaged workflow, and produce a bounded deliverable.
• Input controls: confirm the source files, scope limits, output format, and acceptance criteria before running any script.
• Primary implementation surface: scripts/__init__.py with additional helper scripts under scripts/.
• Parameters to clarify first: input path, output path, scope filters, thresholds, and any domain-specific constraints.
• Output discipline: keep results reproducible, identify assumptions explicitly, and avoid undocumented side effects.

Quick Check

Use this command to verify that the packaged script entry point can be parsed before deeper execution.

python -m py_compile scripts/main.py

Audit-Ready Commands

Use these concrete commands for validation. They are intentionally self-contained and avoid placeholder paths.

python -m py_compile scripts/main.py
python scripts/main.py --help

Workflow

1. Confirm the user objective, required inputs, and non-negotiable constraints before doing detailed work.
2. Validate that the request matches the documented scope and stop early if the task would require unsupported assumptions.
3. Use the packaged script path or the documented reasoning path with only the inputs that are actually available.
4. Return a structured result that separates assumptions, deliverables, risks, and unresolved items.
5. If execution fails or inputs are incomplete, switch to the fallback path and state exactly what blocked full completion.

Features

• Automatic Band Detection: Detect protein band positions in gel images
• Densitometric Analysis: Calculate grayscale/optical density values for each band
• Normalization: Normalize relative to loading control proteins (e.g., GAPDH, β-actin, Tubulin)
• Data Export: Output quantitative results in CSV format

Usage

Basic Usage

# Call in Python
from skills.western_blot_quantifier.scripts.main import WesternBlotQuantifier

# Create analyzer
analyzer = WesternBlotQuantifier()

# Analyze single image
result = analyzer.analyze(
    image_path="path/to/wb_image.png",
    reference_bands=["GAPDH"],  # Loading control band names
    target_bands=["p53", "Bcl-2"],  # Target protein band names
    lane_positions=[0.2, 0.4, 0.6, 0.8]  # Lane positions (relative to image width)
)

print(result.summary())
result.save("output/quantification_results.csv")

Command Line Usage

python -m skills.western_blot_quantifier.scripts.main \
    --input path/to/wb_image.png \
    --reference GAPDH \
    --targets p53,Bcl-2 \
    --lanes 4 \
    --output results.csv

Parameter Description

Output Format

CSV Output Example

Lane,Protein,Raw_Intensity,Background,Corrected_Intensity,Normalized_to_Reference
1,GAPDH,125000.5,5000.2,120000.3,1.00
1,p53,85000.2,3000.1,82000.1,0.68
1,Bcl-2,62000.8,2500.5,59500.3,0.50
2,GAPDH,118000.3,4800.2,113200.1,1.00
...

Return Object

{
    "raw_data": DataFrame,           # Raw optical density data
    "normalized_data": DataFrame,    # Normalized data
    "band_regions": List[Dict],      # Detected band region coordinates
    "statistics": Dict,              # Statistical analysis results
    "figures": Dict                  # Visualization chart paths
}

Installation

pip install -r requirements.txt

Notes

1. Image Quality: High resolution, good contrast grayscale or black and white gel images are recommended
2. Loading Control Selection: Common loading controls include GAPDH, β-actin, Tubulin; selection depends on experimental conditions
3. Background Correction: Supports rolling_ball, median, none three background correction methods
4. Lane Marking: If auto-detection is inaccurate, lane positions can be manually specified

Examples

Example 1: Basic Analysis

from skills.western_blot_quantifier.scripts.main import WesternBlotQuantifier

analyzer = WesternBlotQuantifier()

# Analyze 4-lane Western Blot results
result = analyzer.analyze(
    image_path="experiment_data/wb_gel.png",
    reference_bands=["GAPDH"],
    target_bands=["p53", "p21"],
    lane_count=4
)

# View normalized results
print(result.normalized_data)

# Save charts
result.save_figures("output/")

Example 2: Batch Processing

import glob

analyzer = WesternBlotQuantifier()

for image_path in glob.glob("experiments/*.png"):
    result = analyzer.analyze(
        image_path=image_path,
        reference_bands=["β-actin"],
        target_bands=["Target_Protein"],
        lane_count=6
    )
    result.save(f"output/{Path(image_path).stem}_results.csv")

Algorithm Description

1. Image Preprocessing: Grayscale conversion → Background correction → Denoising
2. Lane Detection: Automatic lane boundary identification based on vertical projection analysis
3. Band Detection: Band localization using 1D Gaussian fitting or peak detection algorithms
4. Optical Density Calculation: Integrate grayscale values in band region, subtract background
5. Normalization: Target protein value / Loading control protein value