Flow Cytometry Cell Counting Beads
 | Many flow cytometers cannot directly provide the cell concentration or absolute count of cells in a sample. Absolute cell counts are generally obtained either by combining a separate cell concentration determination from a hematology analyzer with flow cytometric population data (multiple platform testing) or by adding an internal microsphere counting standard to the flow cytometric sample (single platform testing). Invitrogen now offers CountBright™ Absolute and AccuCheck flow cytometry cell counting beads. |
CountBright™ Absolute Counting Beads
CountBright™ Absolute flow cytometry cell counting beads are a calibrated suspension of microspheres that are brightly fluorescent across a wide range of excitation and emission wavelengths and contain a known concentration of microspheres. Countbright ™ Absolute flow cytometry cell counting beads are similar in size to lymphocytes, so they do not require any changes in instrument settings. For absolute counts, a specific number of counting beads are added to a known volume of sample, so the sample volume per bead is known. The number of beads in a sample tells you the volume analyzed, and allows accurate calculation of cells per microliter in the sample.
The CountBright Absolute flow cytometry cell counting beads give you:
The CountBright Absolute flow cytometry cell counting beads give you:
- Compatibility—with every commercially available instrument because they are loaded with a wide breadth of fluorochromes,
- Versatility—easy to use protocol that works with multiple cell types including lyse/no wash whole blood
- Accuracy—more reliable than multiple platform testing
| Figure 1. Determination of live and dead cells and absolute cell number. Plot of calcein fluorescence collected with a 530/30 nm bandpass filter vs. ethidium homodimer-1 fluorescence, collected with a 610/20 nm bandpass filter, showing clear separation of live and dead cells, as well as counting beads. A mixture of live and heat-killed Jurkat cells (human T cell leukemia) was treated with the reagents in the LIVE/DEAD® Viability/Cytotoxicity Kit; CountBright™ Absolute Counting Beads were added, and the sample was analyzed by flow cytometry using 488 nm excitation. |
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| Description | Ex (nm) | Em (nm) | Quantity | Cat. No. |
|---|---|---|---|---|
| CountBright™ Absolute Counting Beads | UV-635 | 385-800 | 5 mL | C36950 |
AccuCheck Counting Beads
AccuCheck flow cytometry cell counting beads are ideal for clinical applications. They offer a single-platform method for absolute cell counts that combines the advantages of direct flow cytometric immunophenotyping with the use of two different fluorescent beads that serve as a double internal control for pipetting and mixing. A known volume of AccuCheck flow cytometry cell counting beads is added to a known volume of cell sample and the beads are counted along with the cells. Since the concentration of the beads is known, the number of cells/µL is obtained by relating the number of cells counted to the total number of fluorescent bead events.
The AccuCheck Counting Beads give you:
The AccuCheck Counting Beads give you:
- Accuracy—internal control using ratio of two different color beads indicates pipetting accuracy
- Reliability—Single Platform is preferred over multiple platform testing leading to consistency in results
- Compatiblity—Easy to validate with most immunophenotyping experiments
| Description | Ex (nm) | Em (nm) | Quantity | Cat. No. |
|---|---|---|---|---|
| AccuCheck Flow Cytometry Counting Beads | Bead A: 488 Bead B: UV-635 | Bead A: 525-670 Bead B: 525-670 | 10 mL | PCB100 |
