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-nsulphopropyl-mtoluidine (TOPS)/4-AA as a chromogen.
CLINICAL SIGNIFICANCE
Creatinine is the result of the degradation of the creatine, component of
muscles, it can be transformed into ATP, that is a source of high energy for
the cells. The creatinine production depends on the modification of the
muscular mass, and it varies little and the levels usually are very stable.
Is excreted by the kidneys. With progressive renal insufficiency there is
retention in blood of urea, creatinine and uric acid.
Elevate creatinine level may be indicative of renal insufficiency2.
Clinical diagnosis should not be made on a single test result; it should
integrate clinical and other 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
- Spectrophotometer o photometer measuring at 545±20 nm
- Cell holder thermostable at 37ºC
- 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.
NOTES
1. CREATININE CAL: Proceed carefully with this product because due its
nature it can get contamined easily.
2. Calibration with the aqueous Standard may cause a systematic error in
automatic procedures. In these cases, it is recommended to use a serum
Calibrator.
3. Use clean disposable pipette tips for its dispensation.
4. SPINREACT has instruction sheets for several automatic analyzers.
