# Measurements seem strange

You went through [Run QC test](/getting-started/qc-test/run-qc-test.md) and your BactoBox® setup passed.

Is this not the case? Then let's take a step back. Did the [QC test fail](/troubleshooting/qualification-fails.md)? Does your BactoBox® [not even power on](/troubleshooting/power-on-fails.md)?

See also [BactoBox® acting up?](/troubleshooting/bactobox-r-acting-up.md).

<img src="/files/OasOX4U72TWSGnxuMOKW" alt="" class="gitbook-drawing">

## My BactoBox® measurements seem strange

You are here because you measured your sample vial with BactoBox®, but the *cells/mL* or *total/mL* concentration doesn't align with your expectations.

{% hint style="info" %}

### You don't even get a *cells/mL* or *total/mL* concentration?

This means that you got an *error message* instead. See [Error about conductivity](/troubleshooting/qualification-passes-but.../errors-about-conductivity.md), [Error about slow/fast flow](/troubleshooting/qualification-passes-but.../flow-errors.md), or [Error about electrical signal or noise](/troubleshooting/qualification-passes-but.../errors-about-electrical-signal-or-noise.md).
{% endhint %}

Let's narrow it down. We know that your BactoBox® setup works since it passes the [QC test](/getting-started/qc-test.md). In other words, it is *your sample* that we need to take a look at. See the following sections for details.

## I expected better correlation with plate counts

You are here because you do BactoBox® measurements side-by-side with plate counts and the results don't align.

BactoBox® *does* [correlate with plate counts](/encyclopedia/measurements-explained/linearity-and-correlation.md#correlation-with-plate-counts) but it requires that you [prepare your sample](/protocols/prepare-your-sample.md) first. Especially, that you [break up clumps and chains](/protocols/prepare-your-sample/break-up-clumps-and-chains.md).

{% hint style="info" %}

## Plate counts on bacterial clumps and chains

Bacterial aggregates are generally a pain to measure. If your bacteria form clumps or chains, neither BactoBox® nor plate counts give meaningful results.

Plate counts are measured in *colony-forming units* (CFUs). However, a *colony* does not distinguish between single cells and aggregates. What does your CFU number mean then? Answer: "It depends". Not happy with that answer? Neither are we.
{% endhint %}

{% content-ref url="/pages/YsV0SKKpf2HXv6kx1br6" %}
[Linearity](/encyclopedia/measurements-explained/linearity-and-correlation.md)
{% endcontent-ref %}

{% content-ref url="/pages/rKOmTP0TGrQbTj7pggFY" %}
[Break up clumps and chains](/protocols/prepare-your-sample/break-up-clumps-and-chains.md)
{% endcontent-ref %}

## The *cells/mL* concentration is lower than expected

You may have to [customize gating](/encyclopedia/measurements-explained/gating.md) for your BactoBox®. This is an advanced topic. [Reach out to us](mailto:customersupport@sbtinstruments.com) for help.

{% content-ref url="/pages/gtRl1NJmwYvSftxOizIl" %}
[Gating](/encyclopedia/measurements-explained/gating.md)
{% endcontent-ref %}

## In general

Make sure that you [prepare your sample](/protocols/prepare-your-sample.md) so that it follows [the requirements](/encyclopedia/measurements-explained/what-can-i-measure-on.md). See also our list of [applications](/protocols/meta/applications.md) for protocols specific to specific use cases.

{% content-ref url="/pages/STMuLGUm3JqCsg6fbSGq" %}
[Prepare your sample](/protocols/prepare-your-sample.md)
{% endcontent-ref %}

{% content-ref url="/pages/SuKixltv6UwiBZT6EzTv" %}
[What can I measure on?](/encyclopedia/measurements-explained/what-can-i-measure-on.md)
{% endcontent-ref %}

{% content-ref url="/pages/cY6fsaKF7NDsar5vwnWo" %}
[Applications](/protocols/meta/applications.md)
{% endcontent-ref %}

## It's something else

<table data-card-size="large" data-view="cards"><thead><tr><th></th><th></th><th data-hidden data-card-target data-type="content-ref"></th></tr></thead><tbody><tr><td><strong>💻 Create a support case</strong></td><td>This automatically sends us a <a href="/pages/ATfHBRoZQmRg0QvbUCfM">device data bundle</a> from your BactoBox®.</td><td><a href="/pages/7hSoNWkCR12tN6GOgkCv">/pages/7hSoNWkCR12tN6GOgkCv</a></td></tr><tr><td><strong>✉️ Send us an e-mail</strong></td><td>Send an e-mail to our <a href="mailto:customersupport@sbtinstruments.com">support team</a>. Include a <a href="/pages/n7wIC7OULdE7i7cgQX6H">device data bundle</a> with your email.</td><td><a href="mailto:customersupport@sbtinstruments.com">mailto:customersupport@sbtinstruments.com</a></td></tr></tbody></table>


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