# Check remaining cultures

A 1:1 000 dilution worked well for the -8 culture. The remaining cultures from -7 to -4 were seeded with more cells and therefore a dilution factor of 1:10 000 will be used for these overnight cultures. This is achieved through two sequential 1:100 dilutions.

<figure><img src="/files/f9kAUrtMfXrTeJLjgKmb" alt=""><figcaption></figcaption></figure>

{% stepper %}
{% step %}
**Disaggregate cell clumps**

Vortex the vial 1 minute at maximum speed to disaggregate cell clumps. See [Break up clumps and chains](https://help.sbtinstruments.com/protocols/prepare-your-sample/break-up-clumps-and-chains) if your bacterium needs more aggressive disaggregation.
{% endstep %}

{% step %}
**Dilute 1:100**

Transfer 101 µL of your sample to 10 mL of diluent. Vortex 10 seconds at maximum speed.
{% endstep %}

{% step %}
**Dilute 1:10 000**

Transfer 101 µL of the diluted sample to 10 mL of diluent. Vortex 10 seconds at maximum speed.
{% endstep %}

{% step %}
**Measure the diluted sample on BactoBox®**

Transfer the tubing kit to the 1:10 000 vial.

Press <kbd><mark style="background-color:purple;">Measure<mark style="background-color:purple;"></kbd> in Access to start a new measurement.

* Dilution: <kbd>10 000</kbd>
* Label: <kbd>overnight\_-7</kbd> , <kbd>overnight\_-6</kbd> , <kbd>overnight\_-5</kbd> or <kbd>overnight\_-4</kbd> ,

After completing the measurement, Access will automatically calculate the bacterial concentration in the cryo stock in the field <kbd>Cells/mL × Dil</kbd>.
{% endstep %}

{% step %}
**Check remaining cultures**

Repeat above steps with 1:10 000 dilutions of the remaining cultures, in this case vial <kbd>-6</kbd>, <kbd>-5</kbd>, and <kbd>-4</kbd>.

<figure><img src="/files/TilgfCi5GEgAHw7ZP85t" alt=""><figcaption></figcaption></figure>
{% endstep %}
{% endstepper %}

## Summary

You have now determined the cell concentration in the relevant cultures.\
Proceed to the next step: [Choose best seeding ratio](/mpd/workflows/identify-optimal-inoculum-size/choose-best-seeding-ratio.md).


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