Abbott i-STAT 1 System Manual page 202

Target Values
Target values (determined by testing multiple ampules of each level using multiple lots of cartridges and
i-STAT handhelds that have passed the Electronic Simulator test) are printed on a Value Assignment Sheet
posted on the APOC website at www.pointofcare.abbott.
Ensure that the lot number printed on the Value Assignment Sheet matches the lot number on the label
of the ampule and that the software version above the target value table matches the software version in
the handheld.
Ranges
The ranges displayed represent the maximum deviation expected when controls and cartridges are
performing properly.
Should results outside these ranges be obtained, refer to the Troubleshooting section that follows the
Procedure for Testing Controls in the System Manual.
Target Values are specific to the i-STAT System. Results obtained when testing these aqueous controls
with other methods may differ due to matrix effects.
Correction of PO at Extreme Altitude
2
The partial pressure of oxygen in a solution will change as it equilibrates to the surrounding ambient pressure.
The rate of change is faster in aqueous solutions than in whole blood due to the absence of hemoglobin
which binds oxygen. This is of practical significance when testing aqueous solutions on blood gas analyzers
as there will be a detectable shift in the partial pressure of oxygen in the sample as it equilibrates to the
pressure in the flowpath of the analyzer.
The ranges for i-STAT aqueous control solutions are established for the degree of oxygen equilibration
that occurs in cartridges tested at or near sea level. PO
controls and Calibration Verification Set and proficiency (external quality control) samples, can be corrected
for higher altitude environments using the following equations. Observed PO
before comparing them to the values on the Value Assignment Sheet posted on the APOC website at
www.pointofcare.abbott.
Equations:
For PO values below 150 mmHg:
2
PO corrected = PO
2
Where BP is the barometric pressure reading from the Analyzer Status screen.
(Approximate change: For every decrease of 15 mmHg in pressure from 760 mmHg, add
1 mmHg to the observed value.)
For PO values above 150 mmHg:
2
PO corrected = PO
2
Where BP is the barometric pressure reading from the Analyzer Status screen.
(Approximate change: For every decrease of 35 mmHg in pressure from 760 mmHg, add
1 mmHg to the observed value.)
PRECISION
The additive used in the aqueous-based TriControls to simulate the effect of hematocrit in blood samples
results in reduced precision in repeat measurement of electrolytes relative to the precision obtained when
assaying with either standard control/calibration verification materials or whole blood. The imprecision is
related to the concentration of additive. The increase is pronounced at higher levels of indicated hematocrit.
Internal testing of non-Abbott aqueous control materials on the i-STAT System which have hematocrit,
blood gas and chemistry functionalities exhibit similar precision to that observed for TriControls.
14-8
observed + (0.067 x (760 – BP))
2
observed + (0.029 x (760 – BP))
2
Art: 714376-01P
results for aqueous solutions, including i-STAT
2
values should be corrected
2
Rev. Date: 27-Jan-17