Quality control

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Abbreviations

AP	Assay Plugin
CV	Coefficient of variation
FF	FastFinder
LIMS	Lab information management system
QC	Quality control
SD	Standard deviation

General info

The quality control (QC) module can be used for tracking your control results. Here, an overview of the trackings that are created is found. QC trackings can easily be added or inactivated. Using the filters, it is possible to quickly search a specific (sub)set of tracking(s), e.g. all available trackings for an Assay Plugin.

Activating the Quality Control module

To be able to use QC tracking in FastFinder, the QC module needs to be activated. This is either done automatically (by Velsera) when this module is part of the contract or activated at a later moment. In this case, users can activate the QC module in FastFinder. Velsera will then contact the customer to confirm the activation and perform the necessary actions to start using the QC module.

Setting up Quality Control tracking

To create a new QC tracking for an Assay Plugin, the following steps need to be done:

1. Navigate to the Quality control module in FastFinder (left-side column).
2. Click on 'Create new tracking'
3. A fly-over screen will appear that needs to be completed.

In the fly-over screen, all necessary information to set up a tracking can be entered:

• Tracking type: 
  • Target result tracking: track target-related results over time of a Control sample type. The trackable control sample types include negative, positive controls, and quantification standards. 
  • Standard curve tracking: track parameters related to the standard curve over time.
• Tracking name: free text field - name of the tracking as determined by the user.
• Assay: select the Assay Plugin for which the tracking needs to be set up. 
• Instrument type: PCR instrument - only the instruments applicable for the chosen Assay Plugin are possible. Only one instrument can be selected per tracking. The Assay Plugin version is displayed between brackets.
• Instrument: tracking can be performed across all instruments or for a specific instrument.
• Sample type: sample type to which the tracking is applied. The available options are related to the configured control sample types in the Assay Plugin, including Quantification standards. 
• Target: target to which the tracking will be applied. Only one target can be selected per tracking. 

Per tracking, it is possible to define one or more QC setups, for which the following parameters need to be defined (manually). To add additional QC setups: click 'Add QC setup'

• Metric: metric that will be tracked over time.
  • Target result tracking: Cq, raw end fluorescence, end fluorescence
  • Standard curve tracking: efficiency, slope, Y-intercept, R-square.
• Mean: expected mean value of the tracked metric.
• Standard Deviation (SD)/Coefficient of Variation (CV in %): SC or CV boundaries of the tracked metric.

Note, it is only possible to set up a single tracking per Assay Plugin per time. If multiple trackings per Assay Plugin are required, they need to be configured individually. 

Within a QC tracking

If completely set up, the tracking can be easily accessed via the overview. General information about the tracking (configuration) is provided at the top of the screen. For each QC setup that is configured, information can be found in the dedicated block, and the metrics can easily be updated if needed.

The QC data will be visualized using a Levey-Jennings graph. This only includes data from tracked authorized runfiles with this plugin in FastFinder. Note that data is not tracked historically and retrospectively. In the graph, you can click on a certain data point and have the ability to go to the applicable Target Results if desired.  

If a metric is updated during the tracking, in the ‘Historic tracking configurations’ section, there is an overview of the adaptations made during the tracking period. It is also mandatory to add a comment when changing one of the metrics, for example, lot number information can be added.

As also explained earlier, per tracking it is possible to activate multiple QC setups (i.e. for multiple metrics) either during initial setup or later. These can be (in)activated by toggling the button next to the relevant block.

Westgard rules

Alerts in FastFinder Analysis can be set up via Westgard rules. They can be configured either per tracking, or for all trackings simultaneously. To define Westgard rules for a single tracking, access the settings within the tracking in the QC module. A fly-over screen will open allowing the user to activate the relevant rules.

Rules can be activated by toggling the button after which they will be applied to new analyses. You can choose if you want to implement one or more Westgard rules. If all rules are toggled off, no warning or error messages are received upon tracking. However, in the QC module itself, you can always follow up on the control results.

To set up Westgard rules for all active trackings, see Settings - Quality control.

(In)activate a tracking

When a certain tracking is no longer relevant, it can be inactivated. This can be done as follows:

1. Navigate to the QC module in FastFinder.
2. Go to the QC tracking that needs to be inactivated (either by selecting it from the list or by using the search field).
3. Select the tracking.
4. In the top right corner, toggle the 'Active' button to inactivate the QC tracking. 

Note: it is always possible to access and/or re-activate a tracking that has been inactivated by accessing the tracking again and toggling the button. Via the filters, it is possible to quickly obtain an overview of all inactive trackings. 

 

Quality Control integration in Analysis

QC is also integrated in the Analysis module on the FastFinder platform. This allows users to easily access QC tracking data. This includes data per target and per control type for which QC tracking is enabled, e.g. historic tracking over time, and possible violations, …

In the Control results section (Summary tab), it is shown whether or not the control complies with the conditions specified in the QC module. Here, users can quickly review the status of the QC tracking. 

If more detailed information is required, users can navigate to the Quality Control tab within the Analysis module. This tab contains all details regarding QC tracking. Data is shown for each target per control sample type, including the Levey-Jennings chart displaying the tracked historic data over time. 

In case of a violation of the Westgard rules, this information can be found under the relevant target. A violation is handled as an error notification and therefore always requires manual review. There are two options: confirm or ignore the violation.

• Confirm
  The user agrees with the violation, which will result in the control sample that is made invalid. The point in the Levey-Jennings chart will be shown in red. It is up to the user to decide whether to mark all samples for this assay for retest because of this violation or not (see explanation below). In the analysis itself, the decision tree will be executed taking into account an invalid control sample. 

• Ignore
  The user accepts the data as it is and the control will be considered as valid according to the QC. The user can proceed to authorize the analysis. In the Levey-Jennings chart, the point will be shown in black. Note, in this case, it is mandatory to enter a comment that is added to the audit trail. 

It can also be chosen to mark all samples for retest on control-based results, invalidating all samples for that assay in the analysis. This will also be shown in the Analysis results CSV. 

If desired, it is possible to export the results of the QC tracking in the Analysis results CSV. Both the quality control results and QC-related notifications on target level can be visualized in the report:

• QualityControlResult
  Outcome of the QC evaluation based on the implemented QC trackings and Westgard rules of control samples. This is indicated as Valid or Invalid. 

• Target_x_QCnotifications
  QC notifications related to Target x (e.g., Warning: Violation of Westgard rule(s) 1:2s)

• ControlValidity
  Both the QualityControlResult (described above) and the control validity of the assigned controls (regular assay target from PCs/NCs in the control results section) are reported. If one of them is invalid, the ControlValidity will be reported as ‘invalid’.

Customization of the Analysis results CSV (to include or exclude the above parameters) can be done in FastFinder under Settings > Analysis results CSV. As the CSV is exported to the LIMS system, it is important to ensure that any changes made in the CSV are supported by the LIMS platform. It is recommended to contact your local IT department for more information on this topic.

Relevant articles

Settings - Quality control