Bradford Protein Assay Calculator
Generate a Bradford assay calibration curve and calculate unknown protein concentrations from absorbance measurements.
Input & Computation
This is a research calculator, not a clinical diagnostic tool. Build a standard curve for each assay run, review replicate CV and R\u00b2, and use only the concentration range validated for your specific reagent and protocol.
Assay Configuration
Interpretation Guide
Curve Models
Linear: y = mx + b
Quadratic: y = ax\u00b2 + bx + c
Unknown: x = (y \u2212 b) / m (linear) or root selection (quadratic)
Replicate Statistics
Mean = \u03a3x\u1d62 / n
SD = \u221a(\u03a3(x\u1d62 \u2212 x\u0304)\u00b2 / (n\u22121))
CV% = (SD / x\u0304) \u00d7 100
Evidence & References
Bradford MM (1976)
A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Analytical Biochemistry 72(1–2):248–254.
Bio-Rad
Bradford Protein Assay guidance and protocol documentation. Application notes for Coomassie Brilliant Blue G-250 based protein quantification.
Research calculator \u2014 not a clinical diagnostic tool. Linear: y = mx + b. Quadratic: y = ax\u00b2 + bx + c. Unknowns solved by inverse interpolation within the calibration range. R\u00b2 is a fit indicator, not proof of assay validity.
PM Lab Suite
Clinical Laboratory Intelligence Platform
When to Use
- Quantifying protein concentration from Bradford (Coomassie) absorbance readings at 595 nm
- Building a standard curve with BSA or gamma globulin standards
- Calculating unknown sample concentrations with dilution factors
- Reviewing replicate CV and calibration R² before reporting results
Common Pitfalls
- Protein-to-protein dye response differs — results depend on the selected standard
- Detergents and other substances may interfere with Bradford assays
- A high R² alone does not establish assay acceptability
- Samples outside the calibration range should be diluted or re-assayed
- Blank correction and dilution factors must reflect the actual experimental procedure