Cell Counter CASY
Cell counting & quality control with no limits

Cell Counter and Analyzer CASY

Cell Counter & Analyzer CASY

The Cell Counter & Analyzer CASY, is your ideal partner for counting a wide range of cells. With variable cell size from large stem cell aggregates to small yeast or bacteria, CASY can do it all. The ability of CASY to count cells is perfectly complemented by some great features. As a cell counter, it is highly reproducible, accurate, easy to use with no sample preparation. CASY counts cells quickly and at low cost, providing transparent results and quality that is GMP/GLP compliant.

CASY counts not with a flat image, but with all three dimensions – Seeing Life as it is!

CASY also counts cells using Electronic Current Exclusion (ECE) and Pulse Field Analysis enable the accurate determination of viability without any influence by other variables such as staining or focusing. Viable cells are detected with full cell volume as the cell membrane provides a barrier for current, while dead cells with no membrane resistance have their nucleus detected.

Here is how CASY works: CASY measures the conductivity between 2 electrodes separated by a defined pore. Cells are suspended in CASYton, a defined buffer solution. Cells pass through the pore generate an electrical pulse that correlates with the volume of the cell with a GMP/GLP compliant precision allowing a maximum variation below ±2%.

With CASY cell counter, aggregates are not a problem. During counting, CASY uses mathematically correct volume-based aggregation correction. Mean volume and mean size even are calculated by determining how often a single cell fits into each aggregate detected. This is ideal when working with induced pluripotent stem cells (iPSC).

CASY’s cell counter and analyzer technology gives all-round information about your cells in a very short time. Your cell count, volume, aggregates and homogeneity are identified as well as any contaminations wit only 20-50 µl volume of your samples.

Generations of scientist have successfully trusted CASY cell counter and analyzer for decades. Its cell count and analysis performance are continuously improving as proven by its use in several thousands of publications globally and increasing each year. CASY cell counter and analyzer has been used for all kinds of cells. Whether you are analyzing PBMCs, T-cells, primary cells, bacteria, fungi or algae, CASY can do it. CASY can be equipped with up to 3 different capillaries, each optimized for a certain group of applications. Same time, switching between capillaries is easy and takes only minutes. No compromises or tradeoffs, whether you work with cell lines or primary cells, PBMCs or stem cells, yeast or bacteria. The easily exchangeable capillaries get you ready for the future.

CASY puts precision back in counting with reproducibility unmatched by other counters available. There is no need anymore to spend any time thinking about which counter may be the best one.

CASY – can do it all.

CASY meets all demands supremely

  • Highest reproducibility and accuracy for anything you want to analyze
  • No sample preparation, easy use
  • High speed at low cost
  • Transparent results and quality control
  • Thousands of publications and thousands of installations
  • GMP/GLP compliant
  • Optional 21CFR Part 11 module

Cell Counter & Analyzer CASY

Cell Counter & Analyzer CASY

CASY Cell Counter & Analyzer – always the best choice, whatever you want to analyze. From large stem cell aggregates to small yeast or even bacteria. CASY provides unmatched precision and reproducibility.

CASY can do it all – the unique detection mechanism will support you even with challenging applications.

CASY – the principle

Cell Counter & Analyzer CASY

CASY measures the conductivity between 2 electrodes separated by a defined pore. Cells are suspended in CASYton, a defined buffer solution. During measurement, cells passing through the pore generate an electrical pulse. The intensity of the signal directly correlates with the volume of the cell. Hence CASY detects the volume of each cell passing through the pore.

For hundreds of our GMP/GLP customers we regularly recertify a consistent precision allowing a maximum variation below ±2%.

Stain Free Viability Control CASY Cell Counter


See life as it is – stain-free viability control.

CASY’s superior detection technology combining Electronic Current Exclusion (ECE) and Pulse Field Analysis (integration of cell signal at 1MHZ while passing through the pore) enable the accurate determination of viability without any influence by staining, focusing, etc.

Viable cells are detected with full cell volume as the cell membrane provides a barrier for current.
Dead cells have lost resistance from cytoplasmic membrane. Instead the much smaller volume of the nucleus is detected that can very well be distinguished.

Aggregation CASY Cell Counter

Aggregation – nothing to worry about.

As CASY determines the volume of each cell with a precision of ±2%, it does the same with aggregates. Unlike optical measurements which either ignore aggregates or try to draw some rings into rather low contrast images of them, CASY uses mathematically correct volume-based aggregation correction. Basically, CASY will see how often a single cell fits into each detected aggregate. Mean volume and size even indicate changes in the level of aggregation, for example with induced Pluripotent Stem cells (iPSC).

The only thing CASY cannot beat is statistics – CASY provides precise, accurate and reproducible results over a wide range of cell concentration. The only limit is given by statistical significance. In other words, counting only 300 cells will result in higher variation and standard deviation compared to counting more than 1.000 or even 10.000 cells per measurement. But even for very low concentrated cells, especially when they are very valuable to you or limited in amount, CASY has a solution to improve results – simply increase the measured volume to up to 3.6ml.


For the results shown in the figure on the left, customers from Switzerland prepared 6 measurements of keratinocytes and compared the results. Even before looking at the results in numbers, the overlay of size distributions shows the high reproducibility of results. The high reproducibility which is independent of users and locations make CASY a great instrument in Biotech or Pharma especially when operations are mirrored at different locations.

Size matters - what cell volume can tell you

CASY’s golden rule: If you haven’t changed anything, but the size distribution looks different – Pay attention: There may be something you don’t know about your cells.

CASY’s volume based cell size distribution provides much more information than merely size. It can:

  • Show level of homogeneity of cells
  • Identify and quantify aggregation
  • Provide indication of multiple cell types in a culture
  • Provide insight in the status of your cells
  • Warn you in case of contaminations

Volume of cells with CASY Cell Counter

The shape of the peak shows the homogeneity of cells.

Sharp peaks represent extremely homogeneous cells like unstimulated CD4 T Cell or stem cells from cord blood.

Medium size peaks are a more common type of distribution found with many cell types including fibroblasts or lager yeast.

Finally, broad peaks are common size distributions for extremely heterogeneous cells, like mesenchymal stem cells (MSC).

Cells with asymetric shape

Asymmetric peak shape, as seen in this figure is a result of aggregation and can be easily analyzed using CASY’s volume based aggregation correction.

Different cell populations with CASY

CASY Cell Counter and Analyzer is an excellent tool to identify changes in cell size extremely sensitively.

  • Increasing volumes, e.g. (baculo-) virus infection or starvation
  • Decreasing volumes, e.g. osmotic or effect of treatments

Diagram Mixtures of different cell populations

CASY can identify mixtures of different cell population like shown in the resulting data seen in these figures.

  1. Mixture of high & low concentrated cell types, e.g. contamination or unwanted differentiation with stem cells
  2. Mixture of equally concentrated cell types

Diagram Determine Contamination of Media

CASY can also do things which seem impossible for other counters. It can determine contamination of media. Whenever there is a peak in a size range not expected (red), it may be the right time to measure pure media (green) to check for contamination.


CASY, the Legend – Generations of scientist have successfully trusted CASY globally for decades and CASY is continuously improving performance. As a result, CASY has been used in several thousands of publications and the list is increasing each year. A list by far too long to be presented here. Feel free to challenge us! Tell us what you are doing in cell counting and we will come up with a better solution, supported by the right publications.

In 2018 the new CASY was launched combining the existing superior measurement principle with a new state-of-the-art control and analytical software.

CASY Software Overview

Keyboard or Mouse, physical or virtual Keyboard, whatever you choose, one thing remains – the easy and intuitive use of CASY!

The new CASY Software comes in 2 versions. The Control-Version includes all functions to control the instrument and also allows analysis of the generated data. The Analysis-Version equals the other version but without the instrument control module. Hence it allows to analyze your data while others can measure new samples.


CASY Software PBMCs Diagram


CASY Software Trial

Getting curious? Contact us for a free trial version. You can even import existing CASY data from older versions.

Contact us

Some highlights of the new software include

  • User Management (3 different user levels)
  • Analysis of single measurements, Overlays or even Mean results
  • Unlimited number of templates
  • Results are organized in a database
  • Data safety
  • Great reporting tools (customizable)
  • Easy access and export of Meta and Primary Data
  • User Support by wizards, like start up or shut down guide
  • Active Directory user management (module is available as option)
  • 21 CFR Part 11 ready (module is available as option)

CASY in mainstream – counting cell lines

Counting cell lines is one of the easiest tasks for CASY Cell Counter and Analyzer. Data for many cell lines are available for download and the number is increasing steadily. Normally, only use 20µl to 50µl of your cells and see cell concentration, viability, size, biomass and many other parameters within very short time.

CASY Software Cell Lines Diagram and Results

Within 30 seconds CASY determined total count of 10.777. Out of these, 9461 were viable cells, which allows a great precision in determination of viable cell number as well as viability. Even the level of aggregation factor (1.9x) was calculated and included in result. This is just one of the many examples of results measured using CASY.

Only mainstream? CASY can do so much more!

CASY is one of the most flexible counters available.

There is no need to spend much time thinking about which counter may be best for your application.

CASY – can do it all.

No compromises or tradeoffs, whether you work with cell lines or primary cells, PBMCs or stem cells, yeast or bacteria. The easily exchangeable capillaries get you ready for the future.

Know your PMBCs

There are probably millions of PBMCs globally prepared from donor blood every day. The quality is however not only influenced by the selected separation media. It is very well known, that the composition also depends largely on the donor of the blood. The ratio between lymphocytes and monocytes can vary significantly between donors. Understanding these differences has a significant impact on the succes of the next steps performed with the PMBCs.

CASY Software Diagram PBMCs

The overlay shows how dramatically the amount of lymphocytes and monocytes may vary from donor to donor. While the amount is balanced (red) in some cases, it may show a significant higher amount of monocytes (blue) or lymphocytes (yellow).

Cell Culture Media

Don’t miss HiMedia’s Lymphocytes separation Media (LSM) and Cryo Solutions for best results preparing and storing PBMCs.

Cell Culture Media

Every time you measure your PBMCs using CASY Cell Counter & Analyzer you will have full information about the

  • Total concentration of cells
  • Counts/ml of lymphocytes and monocytes
  • Share of different cell types in %
  • and more

Don’t miss HiMedia’s (internal link) Lymphocytes separation Media (LSM) and Cryo Solutions for best results preparing and storing PBMCs.

Track T-cell activation

During T cell activation, cell proliferation and increase in volume are two critical parameters that CASY tracks very precisely at the same time. In the example below, human CD4 T Cells were stimulated with anti-CD3/CD28 Dynabeads.

CASY Diagram T-Cells

“Normal” cluster formation and cell size distribution during CD4 T cell stimulation. (Top) Cluster formation in the initial phase of activation of human CD4 T cells. (Bottom) CD4 T cells increased their cell size from 8 μm in freshly isolated quiescent T cells (green line) to 10 μm after 24 h (blue line) and finally to 12 μm after 48 h of stimulation (red line).

CASY Diagram T-Cells Metabolic Conditions

Cluster formation and cell size development can change significantly under different metabolic conditions like the absence of glucose (A) or in the presence of Lactic acid (B).

Whatever the impact is, CASY will not only provide the exact cell number. You can also analyze very precisely changes in volume in each measurement.

T-Cell Activation with CASY

If you want to know more about this application, download the application “T-cell-activation-CASY-AppNote_OLS”


iPSC - flexible handling, full control

CASY will change the way you work with induced pluripotent stem cells (iPSC). Like for other types of samples, no special sample preparation is required. In case of iPSCs, this is truer than ever before. Choose Trypsin, Accutase, EDTA or maybe another method – CASY will count your cells independent of the level of aggregation. Moreover, Mean Size and Mean Volume make the level of aggregation measurable.

So, stop torturing your cells while preparing them for other counting methods – start using CASY.

CASY Software Diagram IPSCs

Human iPSC have been prepared with Trypsin (orange), Accutase (yellow) and EDTA (red). The level of aggregation is visible easily. Volume based aggregation correction allows counting them with the same easy to use template and to provide robust accurate and reproducible results.

The perfect system for standardization of your workflow from expansion of pluripotent stem cell in 3D with highest yield and homogeneity to differentiation into organoids and more, is our CERO 3D Incubator. Complimentary to the workflow, are cell culture lab consumables by HiMedia and Proteintech:

CERO 3D Incubator and Bioreactor

Easy-to-use, long-term 3D cultivation for great viability.

3D Cell Culture Bioreactor CERO 3D

Cell Culture Media

HiMedia cell culture portfolio in media, supplements and more

Catalog by HiMedia

Cytokines and Growth Factors

Highest grade at lowest price – Authentic human proteins

Proteintech HumanKine

Primary Cells – not a challenge


CASY Software Diagram Primary Cells 


Overlay of human endothelial cells fresh isolated (orange) and after 1st passage (yellow)

Sample of primary cells often contain much debris, dead cells or even other cell types. CASY Cell Counter and Analyzer will help you to overcome issues, making counting easy. In the example shown, the measurement of freshly isolated human endothelial cells was compared with a measurement after the first passage. Even when the fresh material was containing much debris, dead cells and viable cells were much more heterogeneous, counting is not a problem and results are reliable and reproducible.

We have successfully been using CASY for 10 years now. With CASY we are able to carry out reproducible cell culture experiments even when working with highly aggregated cells. CASY allows us to consider cell concentration and aggregation when seeding and harvesting cells, as both are measured by CASY. Measuring accurately cell number, the aggregation factor and the cell volume, gives us the opportunity to express analytical data as concentration per cell. Additionally and the molar amount of a substance within a cell can be calculated (used for example for metal uptake in µM).

Prof. Dr. Julia Bornhorst, Food Chemistry, University of Wuppertal

Cytotoxicity Assays using CASY enable us to perform fast, simple and reliable assessment of anti-cancer drug regimens and the subsequent chemosensitivity of carcinoma cell lines. A major advantage of CASY is that debris and dead cells can be masked in the analysis by a simple cell line specific setup and only viable cells and their aggregates are considered. However, as a complete cell status is recorded, also dead cells and debris data are available at any time.

Dr. J. Weinreich, Experimentelle Onkologie, Universiätsklinikum Tübingen

We study the regulation of cancer cell growth by signaling and metabolism. CASY is the ideal system for us to precisely measure proliferation and cell size of a wide range of cell lines. In this context, the new software makes instrument operation as well as data visualization and organization easy and convenient.

Dr. Wilhelm Palm, Head of the Junior Research Group Cell Signaling and Metabolism, German Cancer Research Center

Insect cell / Baculovirus – stop before they burst

CASY Software Diagram Insect Cells

During baculovirus infection the cell volume of SF9 cells changes significantly. Before infection (red) cells are about 15µm in diameter. During infection, cells (green) grow to sizes of 19µm or more.

CASY Counter and Analyzer is not only able to measure the change in volume. CASY also allows to standardize the process so that infection can be stopped before cells burst.

We have been using CASY for the fast and reliable determination of cell concentrations and cell diameters of our cell cultures for 20 years now. We are still impressed by the high reproducibility of the measurements and the simple, intuitive operation of the device. The associated software offers great options for managing and displaying the measurement results graphically.

Dr. Heike Schwarz, Leitung Abteilung Zellbiologie, DIARECT AG

Erythrocytes and Platelets

CASY Software Diagram Erythrocytes and Platelets

Erythrocytes are the most dominant cell type in fresh blood (orange) and show a peak at about 5.1µm in the case presented. Still CASY can detect populations of active and inactive platelets in fresh blood. After centrifugation Platelets remain (blue) and can be detected separately.

Saccharomyces cerevisiae

One of the most common commercial uses of Saccharomyces cerevisiae is brewing beer. Knowing the exact number of cells and their viability are two very critical parameters in the process, but not easy to obtain. Many breweries rely on CASY throughout the process.

  • CASY works with bottom fermenting and free-floating yeast
  • CASY reliable determines cell concentration and viability
  • CASY detection is not impacted by trub
  • CASY can warn you like in case of contamination with wild yeast or petite mutations

CASY Software Diagram Saccharomyces

CASY will detect and the overlay can make visible smallest changes. In this case normal lager yeast (green) is compared to a sample which was obtained after a wild yeast infection (red).

If you are working with Candida albicans or Candida glabrata or something related, contact us to learn more or ask for a demo.

Algae – watch them bud

CASY Software Digrams Raphidocelis subcapitata

Raphidocelis subcapitata is a sweet water algae that is used in environmental testing. Growth and budding can be synchronized by light. CASY allows to follow the budding process very precisely.

R. subcapitata has a cell size of 6µm and each mother cell buds into 4 daughter cells. As budding begins, increasing numbers of single daughter cells appear. The budding continues over a time period of 4 to 5 hours increasing the number of single buds. In parallel the mother cells at 6µm almost completely disappear. Download the application notes down below.

Algae for Daphnia

In some cases CASY can be used in an indirect way: In this lab, the amount of algae provided as food for Daphnia needed to be standardized. The appetite of Daphnia correlates with water quality. Therefore CASY was used to measure the initial amount of algae and what was left after one hour.

Want to learn more? Download the application note available in the “Downloads” section.

We use CASY cell counter for toxicological studies at a single animal level. The CASY cell counter proved to be an accurate and sensitive instrument for ecotoxicological applications allowing fast, simple and label-free measurements.

Prof. Dr. Konstantinos Grintzalis, School of Biotechnology, Dublin City University

Cultivating bacteria in despair?

Bacteria are growing rapidly and the cell number doubles often in 20 min or less. Counting them can be a real challenge and results are normally not precise or accurate.

Commonly used plating needs a long time until a result is at hand and the accuracy is very limited. One of the problems is that the number of bacteria counted often does not reflect a representative sample due to the high concentration of cells in culture. Alternative methods like measuring optical density (OD) only provide a rough idea of the concentration range.

If you are looking for a fast and precise way to count your bacteria, try CASY. Normally, within 45 seconds CASY will count up to 50,000 cells and provide a precise cell number.

CASY Software Diagram Bacteria Merge

Besides E. coli (top) and B. subtillis a huge number of other different bacteria have already been successfully counted using CASY:

A Leptospira interrogans Salmonella thyphimurium
Acinetobacter baylyi M Serratia marcescens
Aeromonas salmonicida Malikia spinosa Shimwellia blattae
Alcaligenes faecalis Mycobacterium smegmatis Staphylococcus capitis
B N Staphylococcus aureus
Bacillus atrophaeus Neisseria canis Staphylococcus carnosus
Bacillus cereus P Staphylococcus epidermidis
Bacillus subtilis Pasteurella aerogenes Staphylococcus gallinarium
Bacteroides ovatus Pasteurella multocida Staphylococcus saprophyticus
Bordetella petrii Providencia heimbachae Staphylococcus simulans
C Prteus myxofaciens Staphylococcus xylosus
Comamonas acidovorans Pseudomonas aeruginosa Streptomyces spectabilis
Comamonas testosteronii Pseudomonas chloraphis Synechococcus elongatus
E Pseudomonas fluorescens Streptomyces spectabilis
Edwarsiella hoshinae Pseudomonas monteilii V
Enterobacter cloacae Pseudomonas mosselii Vibrio anguillarum
Erwinia aphidicola Pseudomonas pseudoalcaligenes Vibrio parahaemolyticus
Escherichia Coli Pseudomonas putida Y
K Pseudomonas stutzerii Yersina bercovieri
Klebsiella pneumoniae R Yersinia ruckeri
Kluyvera georgiana Rahnella aquatilis i
L S increasing
Lactobacillus Salmonella sp.

Fungi spores

CASY Software Diagram Fungi Spores

Ever wondered whether you have haploid and diploid spores?

Volume based size measurement is very precise and allows to discriminate between haploid (yellow) and diploid (orange) spores from Aspergillus niger. CASY measures many other spores too, just try it!

How to improve counting pollen:

The answer is simple – use CASY.

Article Pollen number counting

A complete workflow was recently published by Kakui et al. and is available for download. CASY provides precise counts for pollen. Even more, CASY can distinguish between pollen of different size or between fully- and undeveloped pollen.

The CASY Cell Counter is a powerful tool for counting pollen numbers. We identified the first pollen-number controlling gene from Arabidopsis thaliana (model plant) by using CASY. CASY was really helpful for our study because we needed to count a lot of samples from different accessions and CRISPR-mutated individuals. The advantages of CASY are high-throughput measuring, reliability, and size distinction. Although pollen grains have a large variation among plant species, we confirmed CASY is able to count pollen grain numbers from a great variety of plant species (for example, Arabidopsis thaliana, Arabidopsis kamchatica, wheat, Japanese cedar, Torenia fournieri, etc.). The CASY cell counter is a crucial tool for my research.

Dr. Hiroyuki Kakui, Graduate School of Science and Technology, Niigata University, Japan

Trypanosoma or Leishmania

Pictogram Trypanosoma

How to measure something with a flagellum, like Leishmania?

CASY can do!

CASY Software Diagram Trypanosoma

CASY’s unique Pulse Field Area technology, detecting cells with 1MHZ while passing the pore, is the basis for the precise detection and exact volume-based size determination of elongated cells even if they carry a flagellum. Leishmania in promastigote stage is a good example and not a challenge for CASY.

Latest CASY news

OMNI Life Science Partners with Cell Microsystems

News | Dr. Andreas Friese

Pioneering journey to productive life science advancements

Read more ›

New OLS Brochure Available

News | Fabian Stautz

OLS released the new 2023 brochure with a comprehensive overview over the key focuses and all available products.

Read more ›

Upcoming CASY events

Currently there are no upcoming events. Have a look at our overview of all events.

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CASYton (10-liter container)

CASYton (10-liter container)

Price on request
Isotonic measurement buffer for all CASY models. Politainer for easy filling of consumption quantities, 1x 10 L

CASYcups (1 box of 1.800 cups)

CASYcups 1box (1.800 cups)

Price on request
Measuring vessels for all CASY models. For dilution of the samples to be measured with CASYton and performing the cell count.

CASYclean 1x 500ml (1 bottle)

CASYclean (1 bottle of 500ml)

Price on request
Capillary and system cleaning agent for all CASY models. To be used for acute decontamination and routine cleaning.

CASYblue 1x 30ml (1 bottle)

CASYblue 1x 30ml (1 bottle)

Price on request
Solution for controlled killing of cell culture cells for accurate adjustment of the left cursor evaluation, 4 x 30 mL

CASY can do – contact us to see what it can do for YOU!

Dr. Joachim Pavel


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