Cell Counting-Viability

Guava ViaCount Assay
for cell counting and viability assessment

The Guava ViaCount® Assay has become a leading standard for viability and cell counting.

Rapid and reliable

The ViaCount Assay provides rapid and reliable determinations of viability and total cell count on all Guava® Systems. Precise, accurate assessments can be made with a wide variety of cell lines, even those with unusual culture conditions or a tendency to aggregate.

Simple

A simple no-wash, mix-and-read procedure, the ViaCount Assay accurately determines absolute total cell counts, viability assessments, and apoptotic percentages with as little as 20 μL of sample.

Accurate and precise

The assay has proven to be more accurate than hemocytometer counting or impedence-based counting over a wide range of cell concentrations without the use of expensive reference beads. And, by providing data on all three types of cell populations in a single measurement, the Guava ViaCount Assay enables a more precise evaluation of culture conditions and viable cell populations so you can best optimize culture conditions. Precise, accurate cell counts provide more consistency for experiments that depend upon accurate determination of viable cells for success, such as ELISpot, cell-based fluorescence assays, or cytokine production assays.

Distinguishes viable, dead, and apoptotic cells

The ViaCount Assay distinguishes viable and non-viable cells based on differential permeabilities of two DNA-binding dyes in the Guava ViaCount® Reagent. The nuclear dye stains only nucleated cells, while the viability dye brightly stains dying cells. This proprietary combination of dyes enables the Guava ViaCount Assay to distinguish viable, apoptotic, and dead cells. Debris is excluded from results based on negative staining with the nuclear dye.

Key features include

• No-wash, mix-and-read, tube- or 96-well plate** procedure
• Analyzes viability of single cells
• Counts up to ten times faster than manual methods; assay complete in about 10 minutes for single sample, about 35 minutes for plate
• Handles low-density and small-volume cell samples
• Works with adherent and suspended cells and non-mammalian* cells
• Delivers direct, absolute cell counts and population percentage
• Data compatible with third party analysis software
• Runs on Guava PCA, PCA-96, EasyCyte Mini, and EasyCyte Plus Systems
  

**Recommend using ViaCount Flex Reagent with plate-based protocols 

*Requires Guava ViaCount Flex Reagent Kit

The Guava ViaCount Family of Reagents also includes formulations to accurately count adherent cells or non-mammalian cell lines.

The Guava ViaCount® Cell Dispersal Reagent (CDR) is an accessory reagent for the Guava ViaCount Assay. ViaCount CDR is an enzymatic reagent that gently disaggregates clumped cells in suspension, improving the accuracy and precision of cell counts. The formulation of ViaCount CDR has been optimized for use with Guava ViaCount Reagent and Guava Systems.

 
The ViaCount Flex Reagent is useful for:

• Low density cell samples: The ViaCount Flex Reagent provides accurate, reproducible assessments for samples too dilute to be counted with standard hemacytometers

• Cell lines that stain heterogeneously: For these cell lines, the ViaCount Flex Reagent facilitates gate settings by providing tighter staining patterns than the original ViaCount Reagent. 

The Viacount Flex Reagent for Challenging Samples further expands the ability to work with:

• Non-mammalian cell lines such as SF9 insect cells and other cell lines with unusual culture conditions.

Key references 

Ogasawara K, Hamerman JA, Hsin H, Chikuma S, Bour-Jordan H, Chen T, Pertel T, Carnaud C, Bluestone JA, Lanier LL. Impairment of NK cell function by NKG2D modulation in NOD mice. Immunity. 2003;18(1): 41-51.

Arase H, Mocarski ES, Campbell AE, Hill AB, Lanier LL. Direct recognition of cytomegalovirus by activating and inhibitory NK cell receptors. Science. 2002;296(5571):1323-1326.

Cerwenka A, O'Callaghan CA, Hamerman JA, Yadav R, Ajayi W, Roopenian DC, Joyce S, Lanier LL. Cutting edge: the minor histocompatibility antigen H60 peptide interacts with both H-2Kb and NKG2D. Journal of Immunology. 2002;168(7):3131-3134.

Ogasawara K, Yoshinaga SK, Lanier LL. Inducible costimulator costimulates cytotoxic activity and IFN-gamma production in activated murine NK cells. Journal ofImmunology. 2002;169(7):3676-3685.

Phi-Wilson J, Harvey J, Goix P, and O’Neill R. A technology for the rapid acquisition of cell number and viability. American Biotechnology Laboratory. 2001; pp 34-36.

Mascotti K, McCullough J, Burger SR. HPC viability measurement: Trypan blue versus acridine orange and propidium iodide. Transfusion. 2000;40(6):693-696.

Altman SA, Randers L, Rao G. Comparison of trypan blue dye exclusion and fluorometric assays for mammalian cell viability determinations. Biotechnology Progress 1993;9:671–674.

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