Rev. Date: 03-Aug-12 Art: 714183-00T
CREATININE/CREA
Creatinine is measured amperometrically. Creatinine is hydrolyzed to creatine in a reaction catalyzed by
the enzyme creatinine amidohydrolase. Creatine is then hydrolyzed to sarcosine in a reaction catalyzed
by the enzyme creatine amidinohydrolase. The oxidation of sarcosine, catalyzed by the enzyme
sarcosine oxidase, produces hydrogen peroxide (H
2
O
2
). The liberated hydrogen peroxide is oxidized at
the platinum electrode to produce a current which is proportional to the sample creatinine concentration.
Creatinine
Amidohydrolase
Creatinine + H
2
O
Creatine
Creatine
Amidinohydrolase
Creatine
+ H
2
O
Sarcosine
+ Urea
Sarcosine Oxidase
Sarcosine
+ O
2
+ H
2
O
Glycine
+ Formaldehyde + H
2
O
2
H
2
O
2
O
2
+ 2H
+
+2e
--
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 creatinine, as part of the i-STAT System, is for the quantitative determination of creatinine in
whole blood on the i-STAT handheld.
Creatinine measurements are used in the diagnosis and treatment of renal diseases, in monitoring renal
dialysis, and as a calculation basis for measuring other urine analytes.
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 creatinine, a list of reactive ingredients is indicated below:
Reactive Ingredient Biological Source
Creatinine N/A
Creatine Amidinohydrolase Actinobacillus sp.
Creatinine Amidohydrolase Microbial
Sarcosine Oxidase Microbial
Metrological Traceability
The i-STAT System test for creatinine measures creatinine amount-of-substance concentration in the