photo of a Countess™ II Automated Cell Counter

Fast, easy, affordable brightfield cell counting

The Invitrogen Countess II Automated Cell Counter uses trypan blue staining combined with an autofocus mechanism and sophisticated image analysis algorithm to obtain accurate cell and viability counts in as little as 10 seconds.

Accuracy—eliminate the subjectivity of manual cell counting and minimize user-to-user variability
Speed—count live and dead cells and measure viability and average cell size in as little as 10 seconds
Convenience—a capacitive touchscreen and simple user interface provides quick startup and requires minimal training

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Compare Countess II and Countess II FL cell counters

Start counting cells in 3 simple steps

See the automated cell counter that works with a reusable slide

The Countess II FL Automated Cell Counter was designed to work with a reusable glass slide to help significantly reduce the long-term consumable costs associated with automated counting. Convenient disposable slides are also available.

See the Countess II FL system

Technical specifications
  • Processing time: <10 seconds
  • Sample concentration range: 1 x 104–1 x 107 cells/mL
  • Particle diameter range: ~4–60 µm
  • Cell diameter range: ~7–60 µm
  • Required sample volume: 10 μL
  • USB drive: 4 gigabyte, FAT file system
  • Optics: 5 megapixels, 2.5X optical magnification
Physical characteristics
  • Instrument dimensions: 
    9" (W) x 5½" (D) x 9" (H); 228.6 mm (W) X 139.7 mm (D) x 228.6 mm (H)
  • Weight: 8 lbs
Counting area
  • Area: 2.15 mm x 1.62 mm (3.48 mm2)
    graphic showing larger counting area of Countess II FL compared to hemocytometers
Included in the box
  • Countess USB drive for storing and transferring data to your computer
  • Disposable slide holder
  • 50 Countess disposable slides
  • Power cord and 4 plug adaptors to accommodate most countries
  • Quick reference card (QRC)

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Researchers use Invitrogen Countess II and Countess II FL Cell Imaging Systems in their labs every day. Here's what some of our users have to say:

"Fast count and nice instruments, easy to use!! I love the small counter!"Dr. Xin Xu, Baylor College of Medicine

"It's very easy to use and it also allows me to quickly update my lab notebook so that each experiment uses the same number of cells. Quick and efficient."Lakeisha Tillery, Meharry Medical College

"It outperformed all other competitor's models that we tried."Michael DaCosta, The Jackson Laboratory

"It's very consistent!"Kim Sylvia, Sanford Burnham Medical Research Institute

"It is very effective at counting cells. It works very well."Mairead Bretney, Sanford Burnham Medical Research Institute

"The Countess II makes it very easy to count cells accurately and quickly - the fact that it tells you the dead cell and live cell count is icing on the cake."Faryal Mir, MIT

"We compared to a hemocytometer and the Countess II always obtained very close results. The fluorescent measurements are a great tool for us to quantify the % transfection and transduction efficiency in our experiments. The light cubes used to detect fluorescence are very easy to switch out when more than two fluorescence sources are needing to be detected. The automatic focusing is very effective and accurate with the option to manually focus."David Waynar, Santa Cruz Biotechnology

"This equipment is very useful for the purposes it is used in our lab. We love it!"Kristin Harwood, BioMarker Strategies, LLC

"Great for a quick check of transfection/transduction efficiency. Easy to use and seems pretty sensitive."Alex Peister, Morehouse College

"Great device. Broad range of cell densities that it can handle. Good at distinguishing clumps and counting cells within clumps."Joanna Rzepka, Veterinary Medical Research & Development

"Low maintenance, fast easy accurate cell counts. Easy for students to use and comprehend."Robert Dean, D'Youville College

"A very accurate cell counter and you can use it to count fluorescent cells as well. Excellent product. I'm very happy with it. I highly recommend it."Massimo Ammirante, University of California, San Diego

The result, image, and data files can be easily exported to a USB drive. The result and image files can be saved as .bmp, .jpg, .tiff, or .png files. The data file is saved as a .csv file that can be easily imported into your current analysis software or viewed in Excel software.

A comma-separated values (CSV) file stores tabular data (numbers and text) in plaintext form. Plain text means that the file is a sequence of characters, with no data that has to be interpreted as binary numbers. A CSV file can be opened with any third party software or spreadsheet program. The table below describes the categories of the Countess II data saved as a CSV file and opened with a spreadsheet program.

Category Column Name Description
General A Number Sequential sample run number
B File Name Name of file
C Date & Time Date and time of sample run
D Mode BF-Brightfield
Trypan blue/
E Total concentration Concentration of the entire sample
F Total cells counted Total number of cells counted in the sample
G Live concentration Concentration of just the “live” portion of the sample
H Live cells counted Total number of “live” cells counted
I Dead concentration Concentration of just the “dead” portion of the sample
J Dead cells counted Total number of “dead” cells counted
K Viability (%) Percent viability of the sample based on trypan blue staining
L Average size (μm) Average cell size in microns
General details X Focus value Focal position number
Y BF Light intensity Brightfield light intensity value from 0-100%
Trypan blue/
Brightfield count parameters
Z Live Size min Minimum size of “live” cells in microns
AA Live Size max Maximum size of “live” cells in microns
AB Live Brightness min “Live” adjustment slider value for minimum brightness
AC Live Brightness max “Live” adjustment slider value for maximum brightness
AD Live Circularity “Live” adjustment slider value for circularity
AE Dead Size min Minimum size of “dead” cells in microns
AF Dead Size max Maximum size of “dead” cells in microns
AG Dead Bright min “Dead” adjustment slider value for minimum brightness
AH Dead Bright max “Dead” adjustment slider value for maximum brightness
AI Dead Circ “Dead” adjustment slider value for circularity

Counting has been successfully performed on the following cell lines using the Countess II FL Automated Cell Counter:

Cell Animal Organ
A431 Human Skin
Adipocytes Human Adipose-derived stem cells
Aortic smooth muscle Human Smooth muscle
CHO-M1WT2 Chinese hamster Ovary
CHSE Chinook salmon Embryo
COLO-205 Human Colon
COS-7 African monkey Kidney
HeLa Human Cervix
HepG2 Human Liver
HL-60 Human Blood
J774A.1 Mouse Blood
Jurkat Human Blood
K562 Human Bone marrow
MCF7 Human Breast
MRC-5 Human Lung
NIH/3T3 Mouse Embryo
PBMC Human Blood
PC-12 Rat Adrenal gland
Pulmonary artery endothelial Human Blood vessel
Pulmonary artery smooth muscle Human Smooth muscle
SF-21 Insect Ovary
U266 Human Blood
U2OS Human Bone
Umbilical vein endothelial Human Blood vessel
Whole lysed blood Human Blood