Manage user-defined and calculated control limits

Follow these steps on the QC Charts tab (of the Analysis page) to manage user-defined and calculated control limits.

Depending on the MS injection time frame, filtering results on the QC Charts tab by time frame shows a summary that presents each control with metrics for assay and MS performance. Each metric is color‑coded to indicate whether it is within the control limits (teal) or outside the control limits (orange).

Purpose of control limits

Control limits help determine whether results are expected. The mean provides a historical average, while the upper and lower control limits indicate normal variation. PAS includes default control limits calculated using two standard deviations above and below the mean. Calculated control limits are generated from user data.

Define and use user-defined control limits

1. On the Controls section’s toolbar, select the Control Limits list and select User Defined to open the Control Limits dialog.

2. Along the top of the dialog, select the tab of the control whose limits you want to define (e.g., Digestion Control). Use the scroll arrows to view all tabs.

3. For each control limit, enter a value.

   • Mean — The value to serve as the historical mean.

   • UCL — The value to serve as the upper control limit.

   • LCL — The value to serve as the lower control limit.

4. Select Save.

Define and use calculated control limits

1. On the Controls section’s toolbar, select  Calculate to open the Calculate Control Limits dialog.

2. In the Start Date and End Date fields, enter or select the applicable dates.

3. Select Save.

   A teal background appears on the plots, indicating that data are shown with modified control limits.

   The new control limit date range has been added to the Calculate Control Limits Range dialog, which you can open with the  Limits button.

4. On the toolbar, select the Control Limits list and select Calculated to use the calculated control limits.

Delete a calculated control limit date range

1. On the Controls section’s toolbar, select  Limits to open the Calculate Control Limits Range dialog.

2. Find the date range you want to delete and select its  Delete button.

3. Select Yes to confirm.

4. Select Save.

Exclude an outlier or other data point

Exclude an outlier or other data point from the control limit calculation. Selecting one data point (sample) in a plot excludes the corresponding sample from the other plots. A well containing the mass spec control has 10 reported QC metrics. All other control wells have 11 reported QC metrics.

1. Select  Exclusion to open the Control Limit Exclusion dialog and display a list of samples that are being excluded.

2. Find the data point (sample) you want to remove and select its  Delete button.

3. Select Yes to confirm.

4. Select Close.