Abbott i-STAT 1, Системное руководство

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LAC - 2
Art: 714184-00M Rev. Date: 03-Aug-12
Fluka, >99 % purity). i-STAT System controls and calibration verification materials are validated for use
only with the i-STAT System and assigned values may not be commutable with other methods. Further
information regarding metrological traceability is available from Abbott Point of Care Inc..
Expected Values
Reportable Reference
2
Test/Abbreviation Units* Range Range
(arterial) (venous)
Lactate/Lac mmol/L 0.30 – 20.00 0.36 – 1.25 0.90 – 1.70
mg/dL 2.7 – 180.2 3.2 – 11.3 8.1 – 15.3
To convert a lactate result from mmol/L to mg/dL, multiply the mmol/L value by 9.01.
The i-STAT reference ranges for whole blood listed above are similar to reference ranges derived from serum
or plasma measurements with standard laboratory methods.
The reference range shown above is intended to be used as a guide for the interpretation of results. Since
reference ranges may vary with demographic factors such as age, gender and heritage, it is recommended
that reference ranges be determined for the population being tested.
* The i-STAT System can be configured with the preferred units.
Clinical Significance
Elevated levels of lactate are mainly found in conditions of hypoxia such as shock, hypovolumia, and left
ventricular failure; in conditions associated with diseases such as diabetes mellitus, neoplasia, and liver
disease; and in conditions associated with drugs or toxins such as ethanol, methanol, or salicylates.
2
Hyperlactatemia is an indicator commonly used to detect tissue hypoperfusion, particularly in the case
of sepsis,
3-5
but also in trauma
6-8
and surgical
9-11
settings.
Performance Characteristics
The typical performance data summarized below was collected in health care facilities by health care
professionals trained in the use of the i-STAT System and comparative methods.
Precision data were collected using CLSI guideline EP5-A
12
. Duplicates of each level of control were tested
on three lots of cartridges over 20 days for a total of 120 replicates.
Method comparison data were collected using CLSI guideline EP9-A
13
. Venous blood samples, collected
in sodium heparin Vacutainer
®
tubes, and arterial blood samples, collected in blood gas syringes, were
analyzed in duplicate on the i-STAT System. In the plasma study, a portion of each specimen was
centrifuged, and the separated plasma was analyzed on the comparative method.
Deming regression analysis
14
was performed on the first replicate of each sample. In the method
comparison table, n is the number of specimens in the data set, Sxx and Syy refer to the estimates of
imprecision based on the duplicates of the comparative and the i-STAT methods respectively, Sy.x is the
standard error of the estimate, and r is the correlation coefficient.*
Interference studies were based on CLSI guideline EP7.
15
*The usual warning relating to the use of regression analysis is summarized here as a reminder: For any analyte, “if the data is
collected over a narrow range, the estimate of the regression parameters are relatively imprecise and may be biased. Therefore,
predictions made from these estimates may be invalid”.
12 The correlation coefficient, r, can be used as a guide to assess the
adequacy of the comparative method range in overcoming this problem. As a guide, the range of data can be considered adequate
if r>0.975.