Invitrogen™ CountBright™ Plus Absolute Counting Beads for 100 Tests

Invitrogen™ CountBright™ Plus Absolute Counting Beads are a ready-to-use suspension of highly fluorescent, ~4 µm polystyrene beads designed for absolute cell counting in flow cytometry. These beads offer a precise and reproducible method for quantifying the absolute number of cells per unit volume, especially when used on flow cytometers that do not have built-in volumetric capabilities.

The beads are excitable across a broad UV to IR wavelength range and exhibit bright fluorescence from 385–860 nm, making them compatible with virtually all modern flow cytometers. With >95% singlet content, CountBright Plus beads minimize aggregation, delivering improved counting accuracy and streamlined gating.

Key Features and Benefits

• Broad Laser Compatibility: Fluorescent across the UV to IR spectrum (385–860 nm)
• Accurate Quantification: Enables absolute cell counts without a volumetric flow cytometer
• Uniform Size (~4 µm): Matches the scale of most mammalian and blood cells for optimal comparison
• >95% Singlets: Reduces doublet formation for precise, reproducible analysis
• Convenient Format: Ready-to-use suspension for easy sample preparation and assay integration
• Flow Cytometry Optimized: Ideal for human whole blood, PBMCs, cultured cells, and more

Applications

• Absolute cell counting in research samples using flow cytometry
• Quantification of PBMCs, whole blood, and tissue-derived cells
• Standardization of cell concentration across experiments
• Cell enumeration in viability, proliferation, and cytotoxicity assays
• Bead-based controls for flow cytometry calibration and instrument standardization

Technical Specifications

How It Works

1. Mix CountBright Plus beads with your cell suspension at a known volume.
2. Run the sample on a flow cytometer alongside your fluorescent cell population.
3. Calculate the absolute cell count using the ratio of bead events to cell events and known bead concentration.

CountBright™ Plus Absolute Counting Beads provide a reliable, accurate, and easy-to-use solution for absolute cell quantification in flow cytometry. With broad excitation/emission capabilities and high singlet purity, these beads are essential for quantifying cell populations in research involving blood, tissue, cultured cells, and immunology assays, especially when using non-volumetric cytometers.