Limit of detection

BactoBox® counts individual particles. If there are too few particles, the concentration estimate is too uncertain. If there are too many particles, we can't tell them apart. Therefore, we have limit of detection (LoD). BactoBox® outputs concentrations in these ranges:

• 30 000–5 000 000 cells/mL (3·10⁴ to 5·10⁵ cells/mL)
• 30 000–5 000 000 total/mL (3·10⁴ to 5·10⁵ total/mL)

Target 0.5–4 million cells/mL for fast results

The more things to count, the faster we are certain about the concentration. Give BactoBox® something to work with and it triggers the Fast results feature ⏩.

Make a dilution series and measure the most diluted sample first. Aim for 0.5–4 million cells/mL.

The figure below shows how the LoD influences the BactoBox® output. The figure uses total/mL as an example but the very same thing is true for cells/mL.

Limit of detection (LoD) and how they influence the BactoBox® output.

Don't know the concentration of your sample?

Make a dilution series and measure the most diluted sample first. This avoids clogging your BactoBox® setup. It also avoids carry-over from your previous sample vial.

Once you are above the lower limit of detection (30 000 cells/mL), target 0.5–4 million cells/mL.

Above the upper limit

Cross the upper limit and BactoBox® can no longer tell the particles apart, so it stops with an error instead of a result. A concentration above 5 000 000 particles/ml also risks clogging the flow cell.

Above the upper limit, BactoBox® shows Error 3000 instead of a result.

Discard the sample, clean the device, and measure again at a higher dilution.

Single cell at a time

The following figure shows how both too few and too many cells cause trouble.