The Cellometer X2 Fluorescent Viability Counter from Nexcelom Bioscience is an automated cell counter designed for yeast, small cells and platelets.


Automated Fluorescent Yeast and Small Cell Counting in Less than 60 Seconds

Cellometer X2


Cell Counting is Made Simple

The Cellometer X2 Fluorescent Viability Counter uses fluorescent imaging, bright-field imaging, and pattern-recognition software to rapidly and precisely detect and count individual cells. Cell diameter, concentration, count, and % viability are calculated and reported automatically.

5x faster compared to manual counting: Sample can be loaded, image can be viewed, cells can be counted, and results can be obtained in <60 seconds.

The Cellometer X2 enables hemacytometer users to:

  • Enhance consistency
  • Increase throughput
  • Avoid judgment errors, user-to-user variability, and miscounts
  • Count complex cells (irregular-shaped and clumpy)
  • Make sure that all information is properly captured
Cellometer X2


Fluorescent Analysis

Nucleated cells in a mixed cell population can be identified by fluorescent dyes used to stain DNA. Acridine orange (AO) is a nuclear staining, or nucleic-acid binding, dye that is permeable to both dead cells and live cells. AO stains all nucleated cells to create green fluorescence when imaged with the Cellometer X2 Fluorescent Viability Counter.

Since mature mammalian red blood cells lack nuclei, only mononuclear cells can generate a fluorescent signal. It is easy to count fluorescent-positive nucleated cells. Red blood cells no longer have to be lysed, which saves time and eliminates an additional sample preparation step.

Fluorescent Viability Determination

It is highly advised to use a fluorescent dye, like propidium iodide (PI) for precise viability analysis of cell samples that contain debris. PI is a nuclear staining, or nucleic-acid binding, dye that penetrates dead cells with compromised membranes. This dye creates red fluorescence by staining all dead nucleated cells.

Since the Cellometer X2 Fluorescent Viability Counter can count dead cells in the red fluorescence channel, there is no influence of live cells and debris. With PI, dead cells are clearly seen in the red fluorescence channel.

Cellometer X2


1-Step Yeast Concentration and Viability Analysis Using Cellometer X2

Bright-Field and Fluorescent Imaging

Fluorescent and bright-field images of yeast cells are shown below. Cells that appear in both the fluorescent and bright-field images are dead.

Cellometer X2


The Cellometer X2 Image Cytometer has been particularly improved for a simple, 1-step determination of the viability and concentration of yeast.

The Cellometer X2 Fluorescent Viability Counter is perfect for small and large breweries and research laboratories looking to automate their fermentation monitoring. Performance of the Cellometer X2 Fluorescent Viability Counter has been demonstrated in the largest breweries located in the United States.

Bright-field images can be observed to validate the morphology of cells. Counted cells inside the cell clumps are revealed by counted bright-field images.

Fluorescent images display dead cells for validation of viability outcomes. Analysis of both fluorescent and bright-field images from each sample makes the 1-step determination of viability and concentration feasible.

Yeast Concentration Measurement by Bright-Field Analysis

Single Cell Count

Cellometer X2


De-Clustering of Yeast Cells

Cellometer X2


Chain-Forming Cell Count

Cellometer X2


Yeast Concentration and Viability Measurement by Bright Field and Fluorescence

Viability Measurement Using Propidium Iodide (PI)

While bright-field images are utilized to achieve an overall cell count, fluorescent images are utilized to count dead cells.

Cellometer X2


Viability Measurement by Oxonol

While bright-field images are utilized to achieve an overall cell count, fluorescent images are utilized to count dead cells.

Cellometer X2


Yeast Concentration Measurement by Dual Fluorescence Detection

Yeast Viability by Dual-Fluorescence

Yeast samples are stained 1-to-1 with a combination of AO and PI dual-fluorescence stain. The viability and concentration of yeast are instantly achieved after staining with the Cellometer X2 Fluorescent Viability Counter. Dead yeast cells fluoresce red and live yeast cells fluoresce green.

Cellometer X2


Yeast Vitality by Fluorescent Enzymatic Stain

Using Carboxyfluorescein-AM fluorescent enzymatic stain, yeast samples are stained 1-to-1 for a period of 45 minutes. These samples are then examined for vitality using the Cellometer X2 Fluorescent Viability Counter. While bright-field images are utilized for an overall cell count, fluorescent images are utilized to quantify the active yeast cells.

Cellometer X2


Yeast Cell Cycle Analysis Using Propidium Iodide (PI)

Normal baker’s yeast, stained with Nexcelom Bioscience’s Cell Cycle Staining Kit, is incubated for a period of 60 minutes prior to using the Cellometer X2 Fluorescent Viability Counter to examine the cell cycle.

The following plot shows the population of yeast that is actively dividing. The higher DNA content of yeast is quantified using PI.

Cellometer X2


Automated Platelet Counting in Whole Blood

Fluorescence-Based Platelet Concentration

Measurement of a blood sample stained using Nexcelom Bioscience’s Calcein AM Vitality/Viability Kit is incubated for a period of 20 minutes. Both white blood cells and platelets generate green fluorescence. In addition, cell size gating is used to exclusively count platelets.

Cellometer X2


Exclusion of Debris and Size-Based Counting

Since the Cellometer X2 Fluorescent Viability detects cells depending on morphology, brightness, and size, cellular debris is accurately and easily left out from the counting results.

  • A fluorescent nuclear dye, like AO, can be utilized to more easily detect the nucleated cells in samples comprising debris
  • Cell size parameters can be altered to improve the removal of debris from results and improve the precision of counting a variety of cell sizes
Cellometer X2


A cell size histogram based on the diameter of cells is automatically produced by the Cellometer X2 Image Cytometer. The settings of maximum and minimum cell diameter can be improved to count specific cells present in a sample.

Cellometer X2


Cell Images and Data Tables can be Viewed, Printed and Saved

Fluorescent and bright-field counted images of mouse splenocytes stained with AO are shown below.

Cellometer X2


Bright-field images can be viewed to check the morphology of cells.

Fluorescent-counted images can be viewed to validate the removal of debris or unnecessary cell types, and rectify the counting of cells inside the clumps.

Export Data

Data can be easily exported to Excel for further data sharing or formatting. Data tables and images can be submitted for publication or pasted into PowerPoint presentations.

Save Data

Data and images can be easily saved to a local computer or network.


Data or images can be directly printed from the software screen. The regular printout shows dead, live, and overall count and concentration of cells, cell images, and % viability.

Cellometer X1 vs. X2


Cellometer Yeast Analysis Cellometer X1 Cellometer X2
Bright field imaging mode X X
Single fluorescence imaging mode X X
Dual fluorescence imaging mode   X
Viability using PI X X
Concentration & viability using AOPI   X
Vitality using CFDA-AM   X
Yeast cell cycle X X
Cellometer software for analysis of clumpy and
irregular-shaped cells
Mean diameter and cell size distribution X X
Cell type wizard for creating new cell type parameters X X


Counting Chambers: No Washing or Contamination

The Cellometer Disposable Counting Chambers consist of two separately enclosed chambers with an accurately controlled height. Using a regular single-channel pipette, a 20 µL cell suspension is loaded into the chamber. This chamber is then embedded into the Cellometer cell counter and the cells are finally imaged. This method of sample loading and analysis is simple and suitable for delicate cells.

Cellometer X2


The disposable Cellometer Cell Counting Chambers provide many major benefits:

  • No danger of cross-contamination
  • Elimination of washing saves time
  • The most cost-effective automated counting consumables
  • Decreased biohazard risk to users
  • A controlled volume of samples

Dedicated On-line and On-site Applications Support

At Nexcelom Bioscience, experienced technical support specialists are available from 9:00 am to 5:00 pm EST through phone and online support and can help customers with:

  • Training of novice users
  • Troubleshooting
  • Optimization of counting parameters
  • Generation of new types of cells
  • Installation of a new Cellometer X2 cell counter

Using the “help button” provided at the bottom right of the Cellometer X2 software screen, users can gain instant access to:

  • Submission of a Support Ticket
  • Features and instructions of a software
  • On-line training videos and tutorials

Users can click the “Submit a Support Ticket” button to launch an easy online form that is directly submitted to Nexcelom Technical Support

  • Images are effortlessly connected for applications support and troubleshooting
  • X2 instrument data fields are populated automatically
  • A Nexcelom Specialist can remotely control the Cellometer X2 Image Cytometer for both training and troubleshooting purposes

Nexcelom Field-Based Applications Specialists are also available for:

  • Technical Seminars
  • On-site demonstrations
  • Troubleshooting
  • Training

All applications specialists at Nexcelom Bioscience are fully focused on image-based cell concentration and viability and cell-based assays using Cellometer image-based cytometry.