Continuing calibration verification

A continuing calibration verification (CCV) is a calibration standard at a known concentration. You inject it through the sequence so you can see whether the curve still reads that concentration. The known concentration is the sample Dose.

Quanto quantitates a CCV on the curve of its Cal group, the same way it quantitates an unknown. The curve fit uses Calibration samples. A CCV stays out of Initial, Partial, Bracket, Bracket with borrow, and standard addition. Spike recovery and blank correction leave it alone.

QC and CCV

QC and CCV both report recovery. RecPct is 100 × concentration / dose. DevPct is RecPct − 100. RecFlag uses the recovery window on the sample’s limit group.

A CCV fails when RecFlag is too low or too high.

How to set it up

1. Set the vial Type to CCV. New methods include that type. The import pattern CCV matches a sample name that contains CCV. Give the vial a Dose (the known concentration) and a Cal group. The type column and the navigator sample-type list show the name CCV. Settings → Appearance… → Show sample type symbols prefixes that name with ▲. The option is off until you turn it on.
2. Open the method editor (Method → Edit method…) and View → Limit groups. On the group the following samples use:
   • MaxCcvGap — maximum number of injections between consecutive CCV vials. The count is every injection in that Cal group, in acquisition order, including the stretch before the first CCV and the stretch after the last one. An empty Cal group is one sequence for the batch. Leave MaxCcvGap empty to turn the interval check off.
   • CloseCcv — when this is on, Sample and QC results after the last CCV are flagged, and so is the whole sequence when the batch has no CCV.
3. View → Limits. On the CCV’s limit group, enter Min recovery and Max recovery, for example 80 and 120. A blank number turns that side of the window off. These are the same analyte-level recovery limits used for QC.

Quantitate copies the recovery window onto the batch and evaluates RecPct, DevPct, RecFlag, and CcvFlag with the other limit checks.

What the flags mean

RecFlag is on the CCV result:

DevPct on that result is RecPct − 100. A RecPct of 60 is a DevPct of −40.

CcvFlag is on Sample and QC results. Calibration, Blank, Solvent, and the CCV itself stay OK.

When a result is both after a failed CCV and in a stretch that breaks the interval, CcvFlag is AfterFailedCcv.

Each Sample or QC result uses the MaxCcvGap and CloseCcv of its own limit group. A failed CCV is judged per analyte: a later CCV passes for that analyte when every reported result of that analyte on the vial has RecFlag OK.

The flags are on the result, in Outliers, and on the review list (Rec and Ccv). Reports can read RecPct, DevPct, RecFlag, and CcvFlag.

Where to look

View → Samples and results → Samples shows Type CCV. With Show sample type symbols on, the type column and the navigator sample-type list prefix ▲. The sample-type colour is shown either way.

View → Samples and results → Results shows RecPct, DevPct, RecFlag, and CcvFlag.

View → Samples and results → Calibration draws CCV injections as orange diamonds. They sit on the chart and stay out of the fit. Curve points stay circles. The curve’s field options include a CCV checkbox, next to QC.

Import

These vendor sample types become CCV when the file is read:

Shimadzu Control stays QC. OpenLab Control stays Control. SCIEX quality-control samples stay QC unless the sample name is a verification name.

The example batch ccv.qtb has one low CCV (RecPct about 60, DevPct about −40) and one gap that is longer than MaxCcvGap. See Example batches.