Countess II FL Automated Cell Counter

Advanced autofocusing and counting algorithms

The Countess automated cell counters contain advanced autofocusing and counting algorithms to allow you to quickly and accurately identify and count cells within a population (Figure 1). Countess instruments are compatible with a broad range of cell types and cell lines, and we have validated their use on a number of commonly used cell lines. Upon insertion of the slide the Countess instrument will automatically focus on cells, which helps to minimize user variation associated with manual focusing. Cells between ~7 µm and 60 µm and in suspension at a density of 1 x 10⁴ to 1 x 10⁷ cells/mL are optimal for counting.

• Download the application note:  Comparison of cell counting using Countess II Automated Cell Counters vs. hemocytometers

Figure 1. User variability counting with a hemocytometer compared to using a Countess II instrument. Identical samples of A549, COS-7, HeLa, and U2OS cells were counted by three different operators using a Countess II Cell Counter and then manually with a hemocytomer and microscope. The user-to-user variability for the hemocytometer is much higher than for the Countess II instrument.

Time savings

The additional time it takes to manually count cells using a hemocytometer (up to 5 minutes) compared to counting with the Countess II automated cell counters (10 seconds) is often overlooked as an added cost. An individual counting five slides per day (two samples per slide) can save ~10 hours per month by switching to an automated counter with a reusable slide. The time savings increases to ~15 hours per month when using disposable slides (Figure 2). This additional time can be applied to other activities in the lab, resulting in a significant advantage when switching from manual to automated cell counting.

Figure 2. Estimated hours saved per month when switching from counting cells with a hemocytometer to using an automated cell counter.

Accuracy comparable to flow cytometry

Flow cytometry and manual cell counting with a hemocytometer and microscope are the gold standards for fluorescent protein expression analysis, but both require advanced training for users and relatively expensive instrumentation. The Countess II FL Automated Cell Counter has two optional, user-interchangeable fluorescent channels. The colors collected are determined by the insertion of individual light cubes; more than 20 light cubes are available. 

The Countess II FL Automated Cell Counter is able to count fluorescent cells with comparable accuracy, but with faster turnaround and greater cost-effectiveness while reducing user-to-user variability (Figure 3).

Figure 3. Comparison to flow cytometry with PBMCs. Invitrogen™ EVOS™ GFP and Texas Red™ dye light cubes were installed in the Countess II FL instrument. PBMCs were labeled with 5 and 3 μg/mL acridine orange and ethidium homodimer, to identify all cells and dead cells, respectively. The same sample was analyzed in parallel on an Invitrogen™ Attune™ NxT Flow Cytometer, where the Countess II FL results were confirmed.

Full spectrum of fluorescence detection—not limited to GFP and RFP

The Countess II FL instrument has two fluorescence channels. The fluorescent colors collected are determined by the insertion of individual light cubes. With 20 light cubes to choose from, the Countess II FL instrument is not limited to detection of GFP- and RFP-expressing cells. Looking to measure the transfection efficiency of cells transduced with an RFP-expression construct with a blue nuclear counterstain? No problem. Simply add the RFP and DAPI light cubes, and you can effectively count the number of cells expressing the RFP fusion within the total population and accurately determine the transfection efficiency.

A Texas Red light cube is available for optimal analysis of mCherry expressing cells, a very popular and commonly expressed fluorescent protein. To obtain viability information for these cells, simply utilize one of the Invitrogen™ LIVE/DEAD™ fixable dyes that are offered in a range of colors to meet the application need. This spectrum of flexibility is possible using the user-interchangeable EVOS light cubes with the Countess II FL (Figure 4).

• Read the application note: Fluorescent viability assays on the Countess II FL Automated Cell Counter

• Download the application note:  Blood cell counting using the Countess II FL Automated Cell Counter

Request a no-obligation demo in your lab

NOTE: The reusable slide (Cat. No. A25750) is only compatible with the Countess II FL instrument.