Abbott i-STAT 1 System Manual page 199

Ranges The ranges displayed represent the maximum deviation expected when controls
and cartridges are performing properly.
Should results outside the ranges be obtained, refer to the Troubleshooting section
that follows the Procedure for Testing Controls.
Target Values are specific to the i-STAT System. Results obtained from these
aqueous controls with other methods may differ due to sample matrix effects.
Correction of PO at The partial pressure of oxygen in a solution will change as it equilibrates to the
2
Extreme Altitude
surrounding ambient pressure. The rate of change is faster in aqueous solutions
than in whole blood due to the absence of red blood cells containing hemoglobin
which binds oxygen molecules. 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 which occurs in the cartridges at or near sea level. PO
results for aqueous solutions, including i-STAT controls and Calibration Verification
Set and proficiency (external quality control) samples, can be corrected for higher
altitude environments using the following equations. Observed PO
be corrected before comparing them to the values in the value assignment sheet
included with each box of i-STAT controls.
Equations:
For PO
For PO
Art: 714376-01P
values below 150 mmHg:
2
PO corrected = PO
observed + (0.067 x (760 – BP))
2 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 observed value.)
value above 150 mmHg:
2
PO corrected = PO observed + (0.029 x (760 – BP))
2 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 observed value.)
Rev. Date: 27-Jan-17
2
values should
2
14-5