Calibration facts

Certain system monitors, mainly pH monitors, need to be calibrated regularly for correct results.

Most monitors can be calibrated from UNICORN to convert monitor signals to appropriate units for display. For monitors supplied by manufacturers other than GE Healthcare, and for some GE Healthcare monitors, calibration in UNICORN should be performed each time the monitor itself is calibrated.

For most monitors supplied by GE Healthcare, calibration from UNICORN also performs a true calibration of the monitor, adjusting the signal-response level in the monitor.

Calibration access

Monitors can only be calibrated by users with Calibrate/Tune access.

Calibrations made directly on system modules are logged only in the System Control logbook and not in the Calibration page of Documentation dialog box (Evaluation module) or in the Audit trail.

Problem: This means that the Calibration page and Audit trail information might not be up to date.

Solution: Therefore, always calibrate modules using the UNICORN calibration functions in the System Control module when possible.

Different calibration methods are used depending on the type of monitor and system:

• one-point measurement

• two-point measurement

• continuous measurement.

One-point calibration is based on measurements taken at one reference point. The monitor will be calibrated based on an assumed linear response between the reference point and zero.

Two-point calibration is based on measurements at two reference points. The monitor will be calibrated assuming a linear response between the two reference values. It is important that monitors are calibrated in the measuring range for which they will be used, particularly when the response is not linear over the whole operating range of the monitor (see the figures below).

Continuous calibration is based on a value accumulated during a given time. This kind of calibration applies to the sample pump in ÄKTAdesign systems.