Store at 2-8ºC
PRINCIPLE OF THE METHOD
In the first reaction, creatinase and sarcosine oxidase were used in the
enzymatic hydrolysis of endogenous creatine to produce hydrogen
peroxide, that is eliminated by catalase. In the second reaction, the
catalase is inhibitred by sodium azide, and creatinase and 4-
aminoantipyrine (4-AA) were added, and only the creatine generated
from creatinine by creatininase was hydrolyzed sequentially by
creatinase and sarcosine oxidase to produce hydrogen peroxide. This
newly-formed hydrogen peroxide was measured in a coupled reaction
catalyzed by peroxidase, with N-ethyl-n-sulphopropyl-mtoluidine
(TOPS)/4-AA as a chromogen.
CLINICAL SIGNIFICANCE
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.
Clinical diagnosis should not be made on the findings of a single test
result, but should integrate both clinical and laboratory data.
STORAGE AND STABILITY
All the components of the kit are stable until the expiration date on the
label when stored tightly closed at 2-8ºC, protected from light and
contaminations prevented during their use.
R1 and R2 are stable 8 weeks after opening bottle.
ADDITIONAL EQUIPMENT
- MINDRAY BS-120 / BS-200E Autoanalyzer.
- General laboratory equipment.
SAMPLES
- Serum or plasma1.
- Urine (24 h)1: Dilute fresh urine 1/50 with disitlled water.
Multiply the result by 50 (sample dilution factor).
Creatinine is stable 1 day at 2-8ºC.
QUALITY CONTROL
Control sera are recommended to monitor the performance of assay
procedures: SPINTROL H Normal and Pathologic.
If control values are found outside the defined range, check the
instrument, reagents and calibrator for problems.
Each laboratory should establish its own Quality Control scheme and
corrective actions if controls do not meet the acceptable tolerances.
NOTES
1. Calibration with an aqueous standard may cause matrix related bias, it is
recommended to calíbrate using a serum based calibrator.
