How do I evaluate the final concentration of my sample?

Before dispensing, evaluation of particle size distribution of the sample can be done to determine the sample concentration and to estimate the particle and aggregate thresholds.

To do so, we recommend a 30 sec loading with the histogram option activated to assess the time to count (Tcc) as well as the sample distribution.

Tcc corresponds to the time between two events. For Tcc is >5, the time between two events is long and the sample too diluted. In contrary, for Tcc <2, the sample is too concentrated.

IMPORTANT: If the sample is too concentrated, the accurate dispensing of individual cells might be altered! Unfortunately, it is not possible to re-dilute the sample and a new sample must be prepared! Please see the following FAQ: What are the cell sample concentration requirements? for an optimal preparation of your sample.

The sample distribution displays a histogram which reveals the particles sizes following a gaussian curve. These results can be used to define the Particle and Aggregate thresholds (please see FAQ: What are the “Particle” and “Aggregate” thresholds? How do I define them?).

Figure | Electrical signal distribution of a sample. The “particle threshold” was set at 450 ohms.