Protein Assays

Measuring protein concentration

Accurately quantifying total protein concentration is a key step in most experiments and workflows involving isolation, separation, and analysis of proteins. We offer a variety of assay reagents, kits, and standards for protein quantitation by fluorescent or colorimetric detection with fluorometers, spectrophotometers, and plate readers.

Additionally, our products are offered with Dilution-Free protein standards for added ease-of-use with reduced set up time when generating your standard curve. Dilution-Free protein standards are a set of prediluted standards, packaged in a multichannel pipette compatible format which allows you to easily transfer a full dilution series to your microplate, at once.

Selection guide Technical handbook

Which protein assay is right for you?

	Pierce Bradford Plus Protein Assay Kit with Dilution-Free BSA Protein Standard	Pierce BCA Protein Assay Kit with Dilution-Free BSA Protein Standards	Pierce Dilution-Free Rapid Gold BCA Protein Assay Kit	Qubit Protein Broad Range Assay
Choose when	Speed and ease-of-use are important	Accuracy and reproducibility are important	Accuracy and reproducibility are important Speed and ease-of-use are important	Compatibility and convenience are important High-throughput is not important
Best-in-Class Accuracy (low protein-protein variation)		✓	✓	✓
Broad Dynamic Range (>2 mg/mL wide)			✓	✓
Fast (≤ 15 min.)	✓		✓	✓
Dilution-Free Standard Curve Preparation	✓	✓	✓	✓
Dilution-Free Sample Preparation			✓	✓
High-Throughput (compatible with microplate format)	✓	✓	✓
Compatible with Detergents		✓	✓	✓
Compatible with Reducing Agents	✓			✓
Automatic Concentration Calculations with Qubit 4				✓
Automatic Concentration Calculations with SkanIt Software*	✓	✓	✓
*SkanIt software available for Multiskan Ease, Multiskan SkyHigh, Varioskan ALF, and Varioskan LUX microplate readers. Learn more

We now offer Dilution-Free products, comprising both protein assays and protein standards that make protein quantification easy, fast, and accurate. Pierce Dilution-Free products allow you to minimize tedious dilutions and pipetting errors in your protein assays, delivering accurate results while reducing assay setup time by up to 80%. Learn more about our Dilution-Free assays.

Overview of assays

packaging, reagents, and dilution-free tubes for BCA protein assay

packaging, reagent, and dilution-free tubes for Bradford assay

BCA Assays

Copper-based protein assays, including the bicinchoninic acid (BCA) and Lowry methods.

Compatible with most surfactants—even if present in the sample at concentrations up to 5%
Linear response curve (R2 > 0.95)
Less protein–protein variation than the Coomassie dye–based assays
Dilution-Free BSA protein standards for faster assay time and effortless standard curve generation

View all BCA protein assays

Bradford Assays

Coomassie dye-binding assays for fast and simple protein quantification.

Typically faster and easier to perform compared to most protein assays
Performed at room temperature
Compatible with most salts, solvents, buffers, thiols, reducing substances, and metal-chelating agents
Dilution-Free BSA protein standards for faster assay time and effortless standard curve generation

View all Bradford assays and reagents

Fluorescent Protein Assays

Fluorescence-based protein quantification detection methods provide superior sensitivity.

Excellent sensitivity, requiring less protein sample for quantitation
Timing is not a critical factor, so the assays can be adapted for automated handling in high-throughput applications
Good protein-to-protein variation

View all fluorescent protein assays