> 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/troubleshooting/qc-test-passes-but.../measurements-seem-strange.md). # 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/qc-test-fails/qualification-fails.md)? Does your BactoBox® [not even power on](/troubleshooting/power-on-fails.md)? See also [Troubleshooting](https://help.sbtinstruments.com/troubleshooting/). ## 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/qc-test-passes-but.../errors-about-conductivity.md), [Error about slow/fast flow](/troubleshooting/qc-test-passes-but.../flow-errors.md), or [Error about electrical signal or noise](/troubleshooting/qc-test-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](/advanced/measurements-explained/linearity-and-correlation.md#correlation-with-plate-counts) for [active cultures](/mpd/cell-growth/active-cultures.md) but it requires that you [prepare your sample](/advanced/advanced-sample-preparation/prepare-your-sample.md) first. Especially, that you [break up clumps and chains](/advanced/advanced-sample-preparation/break-up-clumps-and-chains.md). If your culture is not in an active stage you may get [Divergence from plate counts](/mpd/cell-growth/divergence-from-plate-counts.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="/spaces/seAjVXi9YrPNSfdp1OXS/pages/1syGVPbewRuraLAYnZwX" %} [Divergence from plate counts](/mpd/cell-growth/divergence-from-plate-counts.md) {% endcontent-ref %} {% content-ref url="/spaces/CaBGkox4Fd7NCFFCF47X/pages/6XQj5Y0iq50hmraaMC6Z" %} [Linearity](/advanced/measurements-explained/linearity-and-correlation.md) {% endcontent-ref %} {% content-ref url="/spaces/CaBGkox4Fd7NCFFCF47X/pages/EGcffKeYOv3648VI6ANB" %} [Break up clumps and chains](/advanced/advanced-sample-preparation/break-up-clumps-and-chains.md) {% endcontent-ref %} ## The *cells/mL* concentration is lower than expected You may have to [customize gating](/advanced/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="/spaces/CaBGkox4Fd7NCFFCF47X/pages/dvIXEQmPOJ0GXnHYBAIt" %} [Gating](/advanced/measurements-explained/gating.md) {% endcontent-ref %} ## In general Make sure that you [prepare your sample](/advanced/advanced-sample-preparation/prepare-your-sample.md) so that it follows [the requirements](/advanced/measurements-explained/what-can-i-measure-on.md). See also our list of [applications](/best-practices/meta/applications.md) for protocols specific to specific use cases. {% content-ref url="/spaces/CaBGkox4Fd7NCFFCF47X/pages/XNy1bmZj4njIufKvBj5M" %} [Prepare your sample](/advanced/advanced-sample-preparation/prepare-your-sample.md) {% endcontent-ref %} {% content-ref url="/spaces/CaBGkox4Fd7NCFFCF47X/pages/mSXWy2nYNmHSnEzHNHEh" %} [What can I measure on?](/advanced/measurements-explained/what-can-i-measure-on.md) {% endcontent-ref %} {% content-ref url="/spaces/eYTtd7c0A325muFr5lMW/pages/cY6fsaKF7NDsar5vwnWo" %} [Applications](/best-practices/meta/applications.md) {% endcontent-ref %} ## It's something else
💻 Create a support caseThis automatically sends us a device data bundle from your BactoBox®./pages/er1nublN79dNDdw51iTT
✉️ Send us an e-mailSend an e-mail to our support team. Include a device data bundle with your email.mailto:customersupport@sbtinstruments.com
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