> 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/get-starter-cultures/from-liquid-culture/determine-concentration-of-inoculum.md).
# Determine concentration of inoculum
We want to inoculate using a well-defined seeding concentration of cells. For this you need to know the cell concentration of the liquid culture used to seed the growth medium. A 1:10 000 dilution is usually suitable for the BactoBox® measurement. See [Hit the right concentration](https://help.sbtinstruments.com/custom/advanced-sample-preparation/hit-the-right-concentration) if the result is not within the working range.
## Step by step
{% stepper %}
{% step %}
**Retrieve a sample of the inoculum**
Swirl the inoculum well to suspend cells and use a sterile serological pipette to collect 1 mL sample. Transfer to a sterile 5 mL centrifuge tube
{% endstep %}
{% step %}
**Disaggregate cell clumps**
Vortex the sample 1 min at max speed to disaggregate cell clumps.
{% endstep %}
{% step %}
**Dilute 1:100**
Transfer 101 µL of T0 culture to 10 mL of diluent. Vortex 10 sec. at max speed.
{% endstep %}
{% step %}
**Dilute 1:10 000**
Transfer 101 µL of the 1:100 dilution to 10 mL of diluent. Vortex 10 sec. at max speed.
{% endstep %}
{% step %}
**Measure**
Transfer tubing kit to the diluted sample. Press Measure and wait for the result to appear on the BactoBox® screen.
{% endstep %}
{% step %}
**Calculate concentration**
Multiply the cells/mL result with the dilution factor, in this case 10 000, to get the cell concentration of the inoculum
{% endstep %}
{% endstepper %}
## Summary
Once you know the cell concentration of the inoculum, proceed to [Inoculate culture](/mpd/workflows/get-starter-cultures/from-liquid-culture/inoculate-culture.md).
---
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