> 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/tutorials/measure-vitroid-tm-growth-curve/summary.md).
# Summary
This tutorial used an *E. coli* Vitroids™ disc to inoculate a shake flask containing LB medium. The initial cell concentration is below the limit of quantification, and approximately 5 hours of incubation are required before the culture can be reliably measured using a 1:100 dilution.
Although it may be tempting to use a lower dilution factor, this will typically result in conductivity errors when using the standard diluent because most growth media have relatively high conductivity.
As the cell concentration increases, the initial 1:100 dilution scheme is replaced by 1:1,000 and later 1:10,000 dilutions.
## Screening for suitable dilution factors
Selecting an appropriate dilution is often the most challenging aspect of BactoBox® measurements. We recommend using the following screening approach.
Prepare a dilution series up to a 1:10,000 dilution and begin by measuring the most diluted sample.
* If the 1:10,000 dilution yields a valid cell concentration, no further measurements are required.
* If the measured concentration is below 30,000 cells/mL, repeat the measurement using the 1:100 dilution instead.
The advantage of measuring the most diluted sample first is that it minimizes the risk of clogging the external filter.
{% hint style="success" %}
## Measure the lowest dilution first when screening for suitable dilution factors
For cultures with unknown bacterial concentration you often screen, try a 1:10,000 dilution first. If the cell concentration is < 30,000 try a 1:100 dilution.
{% endhint %}
## BactoBox® skills
After successfully completing this tutorial you have acquired the following skills:
:bacteria: Disaggregrate bacterial clumps by vortexing
:square-bolt: Hit the right conductivity
:bullseye-arrow: Hit the right concentration
:chart-line-up: Plot a growth curve
:calculator-simple: Calculate growth rate and generation time
## Next steps
Tutorials 1, 2, and 3 provide the basic skills needed to use BactoBox® as a stand-alone device.
After successfully completing these tutorials, you are ready to move on to more advanced studies involving your own cultures and growth media. See [Workflows](/mpd/workflows/bioprocess-workflows.md) for inspiration on potential use cases.
We recommend you see see the [Track growth curve](/mpd/mini-course/track-growth-curve.md) mini course for a brief introduction to tracking growth curves via Access. This provides a powerful way to see your growth curves in real time and skip the manual logs.
---
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