Rev. Date:12-Jul-11 Art: 714176-00L
BUN/UREA
Urea is hydrolyzed to ammonium ions in a reaction catalyzed by the enzyme urease.
urease
Urea + H
2
O + 2H
+
2NH
+
4
+ CO
2
The ammonium ions are measured potentiometrically by an ion-selective electrode. In the calculation of
results for urea, concentration is related to potential through the Nernst Equation.
See below for information on factors affecting results. Certain substances, such as drugs, may affect
analyte levels in vivo.
1
If results appear inconsistent with the clinical assessment, the patient sample should be retested using
another cartridge.
Intended Use
The test for blood urea nitrogen (BUN/urea), as part of the i-STAT System, is intended for use in the in vitro
quantification
of
BUN/urea in
arterial, venous, or capillary whole blood.
Blood urea nitrogen measurements are used for the diagnosis, monitoring, and treatment of certain renal
and metabolic diseases.
Contents
Each i-STAT cartridge contains one reference electrode (when potentiometric sensors are included in the
cartridge configuration), sensors for the measurement of specific analytes, and a buffered aqueous calibrant
solution that contains known concentrations of analytes and preservatives. For cartridges that contain a
sensor for the measurement of urea nitrogen, a list of reactive ingredients is indicated below:
Reactive Ingredient Biological Source
Urea N/A
Urease Canavalia ensiformis
Metrological Traceability
The i-STAT System test for blood urea nitrogen/urea measures blood urea nitrogen/urea amount-of-
substance concentration in the plasma fraction of arterial, venous, or capillary whole blood (dimension
mmol L
-1
) for in vitro diagnostic use. BUN/urea values assigned to i-STAT’s controls and calibration
verification materials are traceable to the U.S. National Institute of Standards and Technology (NIST)
standard reference material SRM909. 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
Test/Abbreviation Units* Range Range
2
Urea Nitrogen/BUN mg/dL 3 – 140 8 – 26
Urea mmol/L 1 – 50 2.9 – 9.4
Urea mg/dL 6 – 300 17 - 56
Urea g/L 0.06 – 3.00 0.17 - 0.56
*The i-STAT System can be configured with the preferred units.
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