Kalibrierung

Kalibrierung is the step that relates a measuring device to a known reference. Material whose value has been established by a higher order method is measured, and the device fixes the relationship between the raw signal it detects and the number it displays. Everything reported afterwards depends on that relationship, because without it the instrument still produces a signal that has no scale to be read against.

The distinction that matters in daily work is between setting the scale and checking it. Kalibrierung sets the scale, while a control measurement checks whether the scale still holds, using material with a known target value that the device was never adjusted to. The two are not interchangeable and neither replaces the other, because a correctly calibrated device can drift afterwards, and a control that passes says nothing about whether the underlying calibration was sound in the first place. That is why interne Qualitätskontrolle and Kalibrierung both belong in the written Qualitätssicherung, rather than one standing in for the other.

Who performs the Kalibrierung depends on the system, and there are three arrangements in practice:

• Many Point-of-Care-Test devices are calibrated during manufacture and carry the calibration data with the consumable, in a chip, a code key or a barcode on the package, so the pharmacy transfers data rather than adjusting anything.
• Other devices expect a calibrator to be measured on site at stated intervals.
• Larger analysers are calibrated by the manufacturer or by a service technician under contract.

The Gebrauchsanweisung states which of these applies, and the operating duties under the MPBetreibV attach to following it and to recording that it was done.

A reagent lot change is where this becomes concrete. Strips, cassettes and reagents are produced in lots and each lot carries its own calibration data, so opening a new lot means entering the new code or measuring the new calibrator before any customer sample is run on it. A control measurement then follows, to confirm that the transfer worked. Skipping the step is not a formality missed, because it shifts every value produced on that lot in one direction and nothing in the printed number reveals it.