> For the complete documentation index, see [llms.txt](https://help.sbtinstruments.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.sbtinstruments.com/mpd/workflows/best-medium/check-remaining-cultures.md).
# Morning measurement
Incubate the cultures until they are all at maximal cell concentrations. For *E. coli* an incubation time of 24 hours is sufficient. We expect the concentration to be between 1 × 1010 and 5 × 1010 cells/mL and therefore a 1:10 000 dilution is usually suitable to get within the BactoBox® upper working range of 5 × 106 total/mL.
The below video demonstrates the sample workup.
{% stepper %}
{% step %}
#### Retrieve a sample
Use a serological pipette to sample 1 mL culture. Transfer to a 5 mL centrifuge tube. Note down the sampling time.
{% endstep %}
{% 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/custom/advanced-sample-preparation/break-up-clumps-and-chains) if your bacterium needs more aggressive disaggregation than this.
{% 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 Measure in Access to start a new measurement.
* Dilution: 10 000
* Label: Growth\_medium\_type . For example LB or TSB.
After completing the measurement, Access will automatically calculate the cell concentration in the culture in the field Cells/mL × Dil.
{% endstep %}
{% step %}
**Check remaining cultures**
Repeat above steps with 1:10 000 dilutions of the remaining growth media.
{% endstep %}
{% endstepper %}
{% hint style="info" %}
### Pro tip: Add information on incubation time to each growth medium type (label)
The Access column [calcHPI ](/software/access/pages/measurement-group.md)(calculated hours post inoculation) is a straightforward way to append incubation time to your measurements. If your cultures were inoculated 24 hours before the first measurement, then add the number 24 to the HPI cells for each label. This will automatically offset the measurements with 24 hours. This is optional, but very convenient.
{% endhint %}
## Summary
You have now determined the cell concentration for the morning measurement. Wait \~4 hours before proceeding to [Noon measurement](/mpd/workflows/best-medium/check-remaining-cultures-1.md).
---
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