Calibration; Understanding Automatic Calibrations - Siemens Rapidlab 1200 Operator's Manual

3 Calibration

Calibration is the process of testing and adjusting the electronic signal from a
sensor in response to a known concentration. Calibration establishes a relationship
between the electrical signal of a sensor and the concentration of the analyte
measured by the sensor. The relationship between the sensor signal and the
concentration (or the log of the concentration) of a measured analyte is linear.
The system determines a straight line calibration curve by measuring the sensor
signal from 2 different reagents of known concentration. Each measurement
defines 1 point on the calibration curve. The system calculates the calibration
offset (y-intercept) and slope using the measured signal and known concentration
as established on the calibration curve. The system determines the concentration
of an unknown patient sample or QC sample by comparing its generated signal
during measurement to the established calibration curve.

Understanding Automatic Calibrations

Calibration of the Rapidlab 1200 systems occurs automatically at prescribed
intervals and requires no operator action.
NOTE:
message informing you that the system is busy contains a Cancel button that lets
you interrupt the calibration. However, if the maximum time between automatic
calibrations has elapsed, the system must complete the calibration before allowing
sample analysis.
The system automatically calibrates the sensors as in the following table:
Calibration
Type
1-Point
Full
* Includes the parameters listed in the 1-point calibration description plus tHb and CO-ox
fractions.
The system can defer a calibration to analyze a sample. In this case, the
Frequency
Maximum of 30 or 60 minutes
between calibrations.
The system determines the
interval by sensor drift.
You can manually initiate this
calibration.
Every 8 hours.
You can manually initiate this
calibration.
Description
Measures 1 reagent of known
concentration to adjust either the
offset or the slope for the
following parameters: pH, pCO
+ ++ +
pO , Na , Ca , K , Cl¯, Glu,
2
and Lac.
Measures 2 reagents of known
concentration to adjust either the
offset or the slope drift for all
parameters.
This calibration also calibrates
the fluid detectors.
02087462 Rev. V
,
2
*