Cellometer K2 Fluorescent Viability Cell Counter

Fluorescent automated cell counter for complex primary samples

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The Cellometer K2 is fast and very accurate. We love that the dye is nuclear to ensure accuracy of the cell counts. Sure beats counting by hand!

Amanda Clark, Biomere

The Cellometer K2 is great and easy to use. It gives clear images quickly. We have been using it for a couple years and never have any problems with it!

Solaema Taleb, IUPUI

The Cellometer K2 is very fast and efficient. It has turned what used to be a hassle in the lab into a breeze!

Andrew Schade, KCAS

Cellometer K2 is very compact, reliable and easy to use. Our lab uses this counter to count live and dead cells for our experiments. It is a very good alternative to flow cytometer for cell cycle and apoptosis studies.

Stanford University

We really like this instrument [Cellometer K2]. We were counting cells manually until now. This has made our life much easier.

MD Anderson Cancer Center

Simple, User-friendly Procedure

Simple, User-friendly Procedure - pipette load sample for Cellometer K2, cell viability counter

Pipette 20µl

Insert Slide

Select Assay & Click Count

View Results in 60 seconds!

Simple, Automated Cell Counting in 60 Seconds

The Cellometer K2 utilizes bright field imaging and dual-fluorescence imaging to quickly and accurately identify and count individual cells. Cell count, concentration, diameter, and % viability are automatically calculated and reported.

Results in less than 30 seconds Load Sample, View Image, Count Cells, and Obtain Results in < 60 seconds

The K2 Allows Users to:

  • Increase throughput
  • Increase accuracy
  • Improve consistency
  • Ensure all data is correctly captured
  • Count difficult cells (clumpy, irregular-shaped)
  • Eliminate judgment errors, miscounts, interference from red blood cells and user-to-user variability

Primary Cell Analysis: PBMCs, Hepatocytes, and more

The Cellometer K2 is specifically optimized for analysis of primary cells from peripheral blood, cord blood, bone marrow, and other complex samples for use in a wide range of research areas, including:

  • Nucleated Cells for Transplantation
  • PBMCs for Immunology
  • Splenocytes for Vaccine Development
  • Stem Cells for Cellular Therapy
  • Tumor Cell Suspensions for Oncology

Dual-color fluorescence allows for staining of live and dead nucleated cells, generating accurate viability results even in the presence of debris, platelets, and red blood cells. Accurate analysis of both ‘messy’ and ‘clean’ samples enables the K2 to evaluate samples at a variety of points throughout sample processing – from initial collection to separation, to cryopreservation.

The Cellometer K2 features assays for analysis of a wide range of primary samples, including:

Hepatocytes - Cellometer K2, cell viability counter


Jurkat - Cellometer K2, cell viability counter


Splenocytes - Cellometer K2, cell viability counter


PBMC - Cellometer K2, cell viability counter


Live / Dead Nucleated Cell Counts using Dual-Fluorescence

Green fluorescent live cell image

Green fluorescent live cell image - Cellometer K2, cell viability counter

Red fluorescent dead cell image

Red fluorescent dead cell image - Cellometer K2, cell viability counter

Why Dual-Fluorescence?

Because bright field cell counting does not differentiate nucleated from non-nucleated cells and trypan blue staining is not as easy to detect as fluorescent staining, dual-color fluorescence is strongly recommended for accurate viability analysis for primary cells. The K2 is equipped with standard assays for dual-fluorescence analysis of primary cells stained with AO/PI.

The AO/PI Method

Acridine Orange, AO, is a nuclear staining (nucleic acid binding) dye permeable to both live and dead cells. It stains all nucleated cells to generate green fluorescence. Propidium iodide, PI, can only enter dead cells with compromised membranes. It stains all dead nucleated cells to generate red fluorescence. Cells stained with both AO and PI fluoresce red due to quenching, so all live nucleated cells fluoresce green and all dead nucleated cells fluoresce red.

Cell-Based Assays: Cell Cycle, Apoptosis and GFP

Cell Cycle

Cell Cycle - Cellometer K2, cell viability counter

Cellometer K2 Image Cytometer has the ability to perform basic cell-based assays such as cell cycle, apoptosis, and green fluorescent protein (GFP) population analysis. These cell-based assays can be performed by exporting image cytometric analysis data to FCS Express from De Novo Software for data analysis and presentation.

For cell cycle analysis, the different cell cycle phases can be analyzed using the cell cycle kit from Nexcelom Bioscience to determine the SubG1, G0/G1, S, and G2/M phase cell population. For apoptosis analysis, using Annexin V-FITC/PI and Caspase 3/8 staining Kit from Nexcelom Bioscience to determine percent apoptotic cell population. GFP expression percent population can also be directly measured using Cellometer K2.

Cellometer K2 SubG1 G0/G1 S SG2/M
AVE 1.0% 51.1% 13.6% 31.1%
STD 0.4% 1.6% 1.0% 1.1%


Apoptosis Negative Control - Cellometer K2, cell viability counter

Untreated (Negative Control)

Healthy Apoptotic Necrotic Debris
AVE 81.9% 8.1% 4.0% 6.0%
STD 1.6% 1.3% 0.4% 1.1%
CV 1.9% 16.1% 9.3% 18.3%

Apoptosis Positive Control - Cellometer K2, cell viability counter

Treated (Positive Control)

Healthy Apoptotic Necrotic Debris
AVE 58.8% 24.7% 13.8% 2.7%
STD 1.9% 1.1% 1.2% 0.2%
CV 3.2% 4.3% 9.0% 9.2%

No Interference from Red Blood Cells, Platelets, or Debris

The dual-fluorescence AO/PI method utilizes nuclear staining dyes that bind to nucleic acids in the cell nucleus. Because most mature mammalian red blood cells do not contain nuclei, only live and dead mononuclear cells produce a fluorescent signal. There is no need to lyse red blood cells, saving time and eliminating an extra sample preparation step. Red blood cells, platelets, and debris are not counted in the fluorescent channels.

The advantage of fluorescent counting for primary cells

These images (right) demonstrate the advantage of fluorescent counting for primary cells. The bright field image shows the combination of nucleated cells, red blood cells, and platelets present in the sample. Only the live and dead nucleated cells are visualized and counted in the green and red fluorescent channels.

Sample Measurement Total nucleated All RBC % RBC n






1.23E+06 8.9% 10
PBMC+1/2RBC Mean






5.82E+05 4.6% 10
PBMC+1/4RBC Mean






2.27E+05 1.8% 10

Fresh human PBMCs (peripheral blood mononuclear cells) were spiked with varying amounts of RBCs (red blood cells.) All cells (nucleated + RBC) were counted in the brightfield channel. Nucleated cells were then counted in the green fluorescent channel. Varying amounts of RBCs (1.8%, 4.6%, and 8.9%) did not affect the nucleated cell count.

Fresh human PBMCs - Cellometer K2, cell viability counter

Several red blood cells are indicated in the bright field image (above, left). The red blood cells are not visible in the fluorescent image (above, right) detecting cells stained with nuclear staining dye.

Cell Images for Data Verification

No two cells are the same.

With the Cellometer K2 Image Cytometer, cell morphology can be immediately viewed on-screen in the bright field image.

Counted cells are indicated on-screen for further verification that cells in the sample are being imaged and analyzed properly. Bright field counted images can be viewed for basic cell counting and trypan blue viability.

Fluorescent counted images indicating counted live and dead nucleated cells can be viewed for dual-fluorescence primary cell viability assays.

Users can confirm that:

  • cells are counted correctly, based on size and shape
  • cells within clumps are being counted individually
  • red blood cells, platelets, and debris are being excluded from results

Bright field counted cell image for Data Verification - Cellometer K2, cell viability counter

Fluorescent counted cell image for Data Verification - Cellometer K2, cell viability counter

The bright field image confirms that individual cells within pairs are being counted and smaller debris is not being counted. In the combined fluorescent counted image, live counted cells are circled in green. Dead counted cells are circled in red.

  • Cell images can be archived and exported for use in publications and presentations.
  • Saved images can be re-counted using default or user-optimized analysis settings

Cellometer Primary Hepatocyte Viability Analysis Method

Due to hepatocytes’ variable morphology, fragile nature, and tendency to clump, traditional manual counting methods can be time-consuming and inaccurate. Because hepatocytes lose viability over time, extended or variable counting times can generate inaccurate and inconsistent viability determinations. Hepatocytes are also too fragile to evaluate using flow cytometry due to flow-induced shear stress. Cellometer image cytometry is the most reliable method for determination of hepatocyte viability.

Dual-fluorescence Staining Procedure

For viability determination, 20µl of hepatocyte sample is mixed with 20µl of Cellometer AO/PI Staining Solution. The acridine orange (AO) dye stains DNA in all nucleated cells, generating green fluorescence and easily differentiating hepatocytes from debris. Propidium iodide (PI) stains DNA in all cells with compromised cell membranes, generating red fluorescence. In cells stained with both AO and PI, the green fluorescence is absorbed by the red fluorescence via FRET (fluorescence resonance energy transfer), so all dead hepatocytes fluoresce red and can be easily counted. The procedure is fast, gentle, and accurate.

Dual-fluorescence Staining Procedure - Cellometer K2, cell viability counter

Bright field image (left) shows the variable morphology of primary hepatocytes. Dual fluorescence image (right) shows counted live hepatocytes (circled in green) and counted dead hepatocytes (circled in red).

Cellometer Analysis - Cellometer K2, cell viability counter

Cellometer Analysis

Immediately after mixing, 20µl of stained sample is loaded into the Cellometer Counting Chamber and inserted into the Cellometer K2 instrument. The sample is imaged directly from the counting chamber. Because the counting chamber is disposable, no washing is required between samples and there is no risk of cross-contamination. Samples are imaged and analyzed using pre-set parameters for primary hepatocytes.

Analysis of Clumpy and Irregular-shaped Cells

Including NCI-60 and clumpy MCF-7 Cells

NCI-60 is a group of 59 human cancer cell lines (originally 60) developed by the National Cancer Institute for screening purposes.

  • 57% of the NCI-60 cell lines are clumpy, contain debris, or display large variations in cell shape or size
  • All 59 NCI-60 cell lines have been successfully validated on the Cellometer Image Cytometer

All 40 of the NCI Comprehensive Cancer Centers use Cellometer Cell Counters.

Clumpy Cells - Cellometer K2, cell viability counter

Clumpy Cells

The MCF-7 breast cancer cell line can be very clumpy. The Cellometer pattern-recognition software identifies and counts individual cells within these cell clumps for accurate analysis (shown above).

Irregular-shaped Cells - Cellometer K2, cell viability counter

Irregular-shaped Cells

The Cellometer cell roundness setting can be adjusted for recognition and counting of irregular-shaped cells, such as RD cells and activated T-cells.

Cell Size Analysis & Size-based Counting

Cell size histogram from Cellometer K2, cell viability counter

The Cellometer K2 Image Cytometer Automatically generates a cell size histogram based on cell diameter.

Because Cellometer generates individual cell size measurements, multiple samples can be overlaid on one histogram enabling analysis of the change in cell diameter over time.

10x Faster than Manual Counting

Hemacytometer under microscope using Cellometer K2, cell viability counter

Counting 1 x 106 cells takes approximately 5 minutes with a manual hemacytometer. Counting live and dead cells sometimes takes twice as long. The Cellometer K2 Image Cytometer calculates cell count and concentration for live and dead cells and % viability in just 60 seconds.

Improve Data Accuracy & Consistency

  • Eliminate Wash Steps
  • Eliminate Judgment Errors
  • Eliminate interference from RBCs
  • Eliminate Recording & Calculation Errors
  • Reduce Counting Time … Run More Experiments

Cellometer Precision

The Cellometer K2 Image Cytometer offers excellent reproducibility, with a %CV (Coefficient of Variation) of <10% for fluorescent concentration and viability measurements. The data (right) is based on four preparations of Jurkat cells stained with propidium iodide, a fluorescent nuclear-staining dye.

Sample N Value Average Live Cell Concentration % Viability CV of Concentration CV of Viability
Jurkat 24 3.61E+06 92.2% 8.9% 1.0%
Human PBMC 10 5.94E+06 96.0% 4.7% 0.5%
Mouse Splenocyte 10 1.86E+07 88.6% 5.6% 0.7%

Imaging / Counting Chambers: No Washing or Contamination

Cellometer disposable images chambers for Cellometer K2, cell viability counter
Cellometer Disposable Imaging Chambers consist of two independent enclosed chambers with a precisely controlled height. Cell suspension of 20 microliters is loaded into the chamber using a standard single channel pipette. The chamber is inserted into the Cellometer cell counter and the cells are imaged. This simple sample loading and analysis method is ideal for fragile cells.

The disposable Cellometer Cell Counting Chambers offer several key advantages:

  • Time savings – no washing
  • No risk of cross-contamination
  • Reduced biohazard risk to users
  • Controlled sample volume
  • Large-depth chambers for large cells
  • Most affordable automated counting consumables

Dedicated On-line and On-site Applications Support

Experienced Nexcelom Technical Support Specialists are available from 8:30 am to 5:00 pm EST for phone and online support and can assist with:

  • Creation of new cell types
  • Optimization of counting parameters
  • Troubleshooting
  • Training of new users
  • Installation of the K2 Cell Viability Counter

K2 help
The help button at the bottom right of the Cellometer K2 software screen gives users instant access to:

  • Software features and instructions
  • On-line tutorials and training videos
  • Submission of a Support Ticket

All Nexcelom Applications Specialists are 100% focused on image-based cell concentration & viability and cell-based assays using Cellometer Image Cytometry.

Nexcelom Field-based Applications Specialists are also available for:

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

Applications for Cellometer K2 Fluorescent Viability Cell Counter



Automatically measure cell size of freshly isolated adipocytes and plot size histogram. DNA staining fluorescence dyes are used to identify cells from lipid droplets. »

Adoptive Cell Transfer Therapy

Adoptive Cell Transfer Therapy

Use Cellometer to perform cell based assays and measure cell size, viability and concentration of cell lines and primary samples used in adoptive cell therapy research. »



Automatically detect and analyze Caspase3 and 8, JC-1, and Annexin V apoptotic events using the Cellometer image cytometery. »

Cell Cycle

Image Cytometry for Cell Cycle Analysis

Automatically measure the cell cycle of mammalian cells. Generated cell cycle histogram allows for easy data analysis and presentation. »

Trypan Blue and AO/PI

Cell Viability Measurement Using Trypan Blue or AO/PI

When should you use trypan blue and when should you use acridine orange/propidium iodide to measure cell viability? »

Cell Viability and Necrosis

Cell Viability and Necrosis

Cell viability is performed using various fluorescent membrane exclusion dyes, such as PI, EB, 7AAD, and others. This assay is performed by enumerating cells in captured bright-field and fluorescent images. And Necrotic cells are detected using propidium iodide. »

Blood Samples

TNC Concentration & Viability for Clinical (Blood) Samples

Analyze fresh and processed blood and bone marrow samples without lysing: no interference from RBCs. »

Cell Size Assay

Cell Size Assay

Performing cell size measurement assay and using cell size to count cells within preset cell size parameters. For adipocytes, stem cells, Sf9 cells, dendritic cells, and others. »

Cancer Cell Lines

NCI-60 Cancer Cell Lines

Automatically measure live cell concentration and viability of cancer cell lines used in oncology research and most of all biology research. »

GFP Transfection Efficiency

Quantitative Measurement of GFP Transfection

Rapidly identify fluorescence positive cells from a sample, analyze individual cell fluorescence intensity, calculate cell concentration, size and determine the GFP transfection automatically. »


Fresh & Cryo Preserved Primary Hepatocytes

Automatically measure live hepatocyte concentration and viability using dual fluorescent nuclear stains, for human, rat, mouse and horse. »


Immunology Research

Automatically quantify cell viability and concentration for a variety of immunologically relevant samples such as: bone marrow, cord blood, slpenocytes, lymphocytes, isolated mononuclear cells, tumor digests, murine samples, and others. »

Insect Cells

Insect Cells

Automatically measure live cell concentration, viability for baculovirus infected insect cells. Cell size histogram live cell concentration and viability are generated within less than 60 seconds using 20 µl sample. »


Peripheral Blood Mononuclear Cells (PBMC)

Automatically measure live cell concentration and viability without lysing red blood cells for consistent results from patient samples. Other cells include splenocytes and bone marrow. »

WBSc in Whole Blood

WBCs in Whole Blood

Automatically measure nucleated cell concentration without lysing red blood cells using nuclear staining dyes (AO), for human and mouse blood. »

Performance of the Cellometer K2 Image Cytometer

Total Cell Concentration Range of Jurkat Cells Measured by Cellometer K2

Concentration Dynamic Range Figure 1 depicts the dynamic range for cell concentration measurements on Cellometer K2. This data set was taken on a concentration series of cultured Jurkat cell line.

Samples from 1 x 105 – 1 x 107 cells/ml can be counted without further dilution.

The %CV at each concentration was below 10%.

Dynamic Range of Total Cells with K2

Figure 1: Table of results for cell concentration dynamic range

Cellometer K2 Repeatability and Consistency

Sample N Value Average Live Cell Concentration % Viability CV of Concentration CV of Viability
Jurkat 24 3.61E+06 92.2% 8.9% 1.0%
Human PBMC 10 5.94E+06 96.0% 4.7% 0.5%
Mouse Splenocyte 10 1.86E+07 88.6% 5.6% 0.7%
Figure 2: Table of results for cell concentration and viability using AO/PI

The results indicate the accuracy of the Cellometer K2 instrument in assessing the viability of Jurkat cells using AO/PI for cell viability. Jurkat, human PBMC, mouse splenocytes were tested at 24, 10, and 10 sample replications, respectively. The viability average was calculated and plotted. The results show the reliability and accuracy of the Cellometer K2 in measuring cell concentration and viability of mammalian cells.

Consistency and Accuracy Comparison to Hemacytometer


N = 20 Hemacytometer Cellometer K2
Average 1.03E+06 1.04E+06
STDEV 6.60E+04 5.57E+04
%CV 6.4% 5.3%

5 µm beads

N = 20 Hemacytometer Cellometer K2
Average 1.07E+06 1.03E+06
STDEV 5.90E+04 5.38E+04
%CV 5.5% 5.2%

The Cellometer K2 is fast and very accurate. We love that the dye is nuclear to ensure the accuracy of the cell counts. Sure beats counting by hand!

Amanda Clark, Biomere

The Cellometer K2 is great and easy to use. It gives clear images quickly. We have been using it for a couple years and never have any problems with it!

Solaema Taleb, IUPUI

The Cellometer K2 is easy to use and great for counting cells that are prone to clumping together. It can’t cell culture without this machine!

Michael Lee, City of Hope
We love the Cellometer K2 system as it can yield accurate cell counts and its performance is superior to that of the Countess II FL Automated Cell Counter. Furthermore, the technical support we have gotten from our Nexcelom representative is outstanding. We also love the fact that the K2 software upgrades are free! Overall, our experience with the K2 instrument and Nexcelom is excellent.
The Cellometer K2 is more accurate than any other cell counter we have tried. We love to use it for our single-cell sequencing platform.
The Cellometer K2 is workable and easy to use for a lab setting. We already have more than four K2 cell counting instruments. This is our preferred instrument to use by far!
The Cellometer K2 is fast and very accurate. We love that the dye is nuclear to ensure accuracy of the cell counts. Sure beats counting by hand! – Amanda Clark, Biomere
The Cellometer K2 allows me to do several counts at once and provides me with an accurate and reliable viability average. Our local Nexcelom representative was amazing and made the transition process extremely simple!
I love the Cellometer K2! I use it nearly daily to count hepatocytes and it is practically effortless! What a great consistent counting instrument.
Overall, we are very pleased with the Cellometer K2. It has saved us time and space, especially during lengthy experiments.
The accuracy of the Cellometer K2 has with an overabundance of cells is great as well as the time it saves each tech to count them!
We have been using the Cellometer K2 for months. It always gives us great reproducibility between cell counts and has increased our throughput drastically! Not only is it much faster than using the hemacytometer, it is much more reproducible between operators.
The Cellometer K2 is great and easy to use. It gives clear images quickly. We have been using it for a couple years and never have any problems with it! – Solaema Taleb, IUPUI
The Cellometer K2 is great! It has been a pleasure working with Nexcelom’s group. All questions have been answered in a timely fashion and customer service has been excellent! – Martin Lagrange, Wuci AppTec
I am working with suspension cell culture, and I need to have precise density and viability of my cells. The precision with the Cellometer K2 is great, very reliable! It takes much less sample and consumes less time! Technically also, the cell counting is very straightforward. There is a much lower chance of errors than with manual counting with hemacytometer. – Shyamtanu Datta, UT Southwestern Medical Center
The Cellometer K2 is easy to use and great for counting cells that are prone to clumping together. It can’t cell culture without this machine! – Michael Lee, City of Hope
We use the Cellometer K2 routinely for a number of cell-based assays. It is very easy to use and gives accurate cell counts!
The Cellometer K2 is great because it only requires 20 uL of sample for cell counting, which is important for when we need to perform counts and are limited with a small number of cells. My lab uses CD34+ cells from patients, so the cells we have are quite costly. The K2 counts are accurate and reliable, and it is quick and easy to count the cells using AO/PI because the reaction occurs quickly. Thanks Nexcelom!
We initially purchased the Cellometer Auto 2000 for our tissue culture cell counting and we were so pleased with it that when the time came to expand our tissue culture room, we purchased a second instrument, the Cellometer K2! The ease of use and the ability to quickly generate live/dead information has been extremely helpful for all our tissue culture needs.
I use the Cellometer K2. I like the fact that it is really easy to use and that you can program different cell types to be sure not to miss your population (sizes vary so much between cell types). Before I started to use this machine, I was mainly counting my cells with a hemacytometer coupled with Trypan Blue staining to check viability. I am now using routinely the K2 with AO/PI for the same purpose. I did the comparison several times between the two methods and the results seem to be concordant. The K2 is really easy to use and really fast! I also like the fact that you can determine right away the proper volume to take for a desired number of cells directly with the software. No more struggle for my students! I highly recommend this machine to everybody who works with students or a lot of different cell types for it is easy to use, robust and fast.
We purchased a Cellometer K2, and all members in our lab love it! It is more accurate and efficient! With auto-counters from other vendors, we always got very confused counts, especially for PBMCs. With the K2, we always get consistent and reliable results! – Mengling Liu, HD Biosciences
We used to use the ViCell to count our cells, but now we use the Cellometer K2. This system is much quicker and requires less of our cells for counting. The system also has a smaller footprint which is nice!
The Cellometer K2 has allowed us to speed up our experiments with PBMCs by giving us quick and accurate cell counts! Our experiments require precise cell densities in order for our data to be reliable and usable for our clients.
The Cellometer K2 has made cell counting easier and more cost-effective. Initially, counts were compared from the K2 to the Flow Analyzers and we find they are comparable, but using the K2 requires less time and sample size!
The Cellometer K2 has helped with the counting of primary hepatocytes. It has made it much easier for accurate counting of cells!
The Cellometer K2 is very fast and efficient. It has turned what used to be a hassle in the lab into a breeze! – Andrew Schade, KCAS
The Cellometer K2 really allows for my experiments to run smoother and quicker. Due to the automated counting, I am able to count all my samples in a fraction of the time!
My lab uses the Cellometer K2 to count splenocytes for our experiments. It is much faster and more convenient than manual cell counting!
The Cellometer K2 makes counting cells very easy and efficient! Going from a manual hemacytometer to the Cellometer saves us a lot of time in the lab!
We use the Cellometer K2 almost every day and my work is so much faster now! My counting is much more accurate and I also improved my cell cycle experiments that are easier and faster thanks to the Cellometer! –Rossella Titone, UT Southwestern Medical Center
The Cellometer K2 makes counting a large number of samples extremely fast! Its fluorescence capabilities makes it a must-have in any biology lab! – Melvin Thomas, UTA
I work with cancer cell lines and some of them grow in clumps making it difficult to count cell numbers. However, by using the Cellometer Mini I am able to get an accurate cell count! I also use the Cellometer K2 for apoptosis assays which makes light of a lot of work, since traditional flow cytometry is time consuming and requires a high number of cells.
The Cellometer Auto T4 and Cellometer K2 make it really easy to obtain cell numbers and makes counting cells less of a task! Basically makes life easy! – Aparna Swarup, Wuxi AppTec
My principle application is the routine counting of peripheral blood mononuclear cells (PBMCs). Our laboratory supports phase one cancer research and PBMCs are the preferred surrogate tissue to assess chemotherapeutic activity for time course studies. We have been measuring PBMCs using a Coulter Z1 particle counter. Unfortunately, red blood cells (RBCs) significantly interfere with this instrument and vary widely between patients. Knowing that pre-analytical steps are often considered to be less important than the ensuing technical aspects of bioanalytical methods and are often insufficiently investigated and thus, underestimated. Also, realizing that pre-analytical variables can significantly impact the reliability of our biomarker measurements; and that standardizing specimen collection, handling, processing, and storage methods definitely minimize pre-analytical errors. The Cellometer K2 offers a solution to the inaccuracy of RBC interference without a Coulter counter and is greatly preferred to the time-consuming manually counting PBMCs with a hemacytometer. – Ken Czambel, The Universitry of Pittsburgh Cancer Institute
I have the Cellometer K2, and this is my fourth instrument from Nexcelom. It is a great workhorse! The machine has been in use constantly for 2 years now with no problems. – Doris Wiener, Lion Biotechnologies
The Cellometer K2 significantly expedites the process of cell counting. I can now compare growth kinetics between large amounts of samples.
The Cellometer K2 has been integral for our continued tissue biorepository success. We have been able to really distinguish between varying cell types.
The Cellometer K2 is definitely in the line of simple to use cell counters. The K2 has sped up our cell counting process enormously. We were accustomed to using the manual method of the hemacytometer, which was a very tedious process. The Cellometer K2 is able to provide us with cell counts within thirty to forty seconds!
The Cellometer K2 is one of the most useful machines I use! It quickly and accurately counts cells for both quality control and fresh orders of PBMCs has increased output.
The ease and efficiency of the Cellometer K2 has decreased the amount of time spent counting cells using the hemacytometer.
The Cellometer K2 has drastically changed our workflow in the lab. We are able to gather cell counts in minutes rather than waiting overnight for colonies to grow on plates. It also cuts down time in the prep of plating and error in plating/counting. The amount of time that the machine has saved us is incalculable – it has allowed us to move projects along much more quickly and with confidence. – Cami Anderson, Synlogic
The Cellometer K2 is always reliable, we use it daily for our cell culture counting and viability assays. The one time we had some questions about it, Nexcelom’s customer service team knew exactly how to fix it. Great service!
With the Cellometer K2, I like the ability to fine-tune individual parameters to modify cell counts if there is an error. The overall use of the machine is great. It has allowed me to gather data in a more high throughput fashion.
I am currently using the Cellometer K2 in our lab, mostly to count T cells, PBMCs, and tumor cells. I use them for cell culture, and later the cells are used for further assays like ELISA and FACS. The instrument is very accurate, especially with AO/PI.
We have been using the Cellometer K2 for about 2.5 years. It is very convenient and robust. The service and technical support are also great. -Yalin Guo, ImmuNext Inc
The Cellometer K2 instrument is a simple, quick, visual cell counting platform. We love the clear images and easily discerned confirmation that the cell count data is real because you can see the count for your own two eyes. It has allowed us to move away from difficult flow cytometer and subjective hemocytometer methods.
The Cellometer K2 has helped us reduce our counting time when we have many samples to count. Side-by-side comparison with manual counting has verified its accuracy. It is easy to use with no routine calibrations startup time is not an issue.
Transitioning to the Cellometer from our previous method using Flow Cytometry, has been smooth and efficient with the help of the great team at Nexcelom. The software is very user-friendly and the instrument is maintenance free. I would highly recommend the Nexcelom Cellometer K2 to other facilities looking to use image-based cell counting systems.

Our customers include: