Abbott i-STAT 1 System Manual page 304

The use of unit-use cartridges frees the i-STAT System from these skilled
maintenance and calibration procedures. It also allows for the design of a
quality control system which automatically monitors those aspects of the
measurement process which are the most likely to impact quality, including the
characteristics of the individual sensors and the operator's actions.
i-STAT's quality control regimen has four aspects, resting on the foundation
of a system design which reduces the opportunity for the type of error which
traditional quality control regimens are designed to detect:
Similarities Although the more significant aspects of i-STAT's quality control regimen are
the quality checks automatically performed with each unit-use cartridge, many
to Traditional
principles of the quality control regimen are similar to traditional regimens.
Laboratory Quality
Control Regimen
Laboratory quality control methods are statistical. They assess the quality of
the measurement process by intermittently inserting pseudosamples (controls)
into the stream of samples being tested.
The approach implicitly assumes that the elements of the measuring
system persist from run to run so that the repeatability and accuracy of the
measurement of patient samples can be predicted by the repeatability and
accuracy of pseudosamples.
The i STAT system uses an analogous approach to monitor the part of the
testing process which persists from run to run – the handheld analyzer.
An Electronic Simulator, which mimics the electrical characteristics of the
signals produced by the sensors, is inserted into the handheld analyzer on
a daily basis. The Simulator produces signals consistent with both very low
and very high concentrations of each of the analytes. The handheld analyzer
causes the Simulator to change the signals via a control signal.
The software in the handheld analyzer measures these signals as it would
measure signals from a cartridge. The software checks the measurements
against predetermined thresholds and indicates their acceptability to the user
via a PASS/FAIL message.
An important aspect of the Simulator is that it mimics the sensitive nature
of the sensor's signals to ensure that the adjacent input channels within
the handheld analyzer maintain the required degree of electrical isolation
from each other to prevent "crosstalk" (see US Patent #51246661 for details).
This cannot be achieved by the traditional internal self-consistency checks
characteristic of modern microprocessor-controlled instrumentation.
20-8
1) A series of automated, on-line quality measurements that monitor the
sensors, fluidics and instrumentation each time a test is performed.
2) A series of automated, on-line procedural checks monitors the user each
time a test is performed.
3) Liquid materials are used to verify the performance of a batch of
cartridges when they are first received or when storage conditions are in
question.
4) Traditional quality control measurements verify the instrumentation
using an independent device, which simulates the characteristics of
the electrochemical sensors in a way which stresses the performance
characteristics of the instrumentation.
Art: 714382-01D Rev. Date: 01-Apr-14