Fast and Convenient Automated Cell Counter

October 20, 2026

BlueskyReddit
Stanford University
Department of Pathology
Postdoctoral Researcher

Overall

Performance

Ease-of-Optimization

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Company:

Thermo Fisher Scientific

Product Name:

Countess™ 3 Automated Cell Counter

Catalog Number:

A49862

I work with multiple cultured mammalian cells for disease and cancer signaling. The Countess 3 simplifies routine cell counting and viability measurements, helping standardize cell numbers for experiments.

Experimental Design and Results Summary

Performance, Range, and Accuracy

The Countess 3 supports cell concentrations of 1x10^4 to 1x10^7 cells/mL, with a cell diameter range of approximately 4–60 µm. Counting is very accurate but depends on sample quality, cell clumping and debris.

Throughput, Workflow Efficiency, and Automation

The instrument processes a sample in approximately 20–30 seconds. Automated focusing, lighting, image capture, counting, viability calculations, and data saving reduce hands-on time and is particularly useful for routine passaging and preparing multiple samples for experiments.

Sample Integrity and Consumable Requirements

The Countess 3 fits one-time use slides with two sample slots. Disposable chamber slides are convenient but create recurring consumable costs. Reusable slides are also supported, by purchasing an adapter to fit a hemocytometer.

Footprint, Facilities, and Daily Maintenance

The instrument is compact and lightweight. It requires a standard power connection and minimal bench space. It does not require any routine maintenance, cleaning, or calibration, making it convenient for daily laboratory use.

Connectivity, Data Output, and Software Compliance

Results and images can be saved to a USB drive and transferred to a computer. The instrument offers automatic data saving and software updates.

Additional Advice

Always pipet 10 µL sample per slot for accurate counting. Do not push in higher volumes.

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Summary

The Good

Fast, automated counting with minimal hands-on time, measures cell viability

The Bad

Counting slides may add recurring costs

The Bottom Line

A convenient instrument for routine cell counting and viability assessment, particularly when consistent cell numbers are important across experiments

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