Creatine kinase is a cellular enzyme with wide tissue distribution in the
body. Its physiological role is associated with adenosine triphosphate
(ATP) generation for contractile or transport systems.
Elevated CK values are observed in diseases of skeletal muscle and after
myocardial infarction1,5,6.
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.
Do not use the tablets if appears broken.
Do not use reagents over the expiration date.
Signs of reagent deterioration:
- Presence of particles and turbidity.
- Blank absorbance (A) at 340 nm 1,00.
ADDITIONAL EQUIPMENT
- Spectrophotometer or colorimeter measuring at 340 nm.
- Thermostatic bath at 25ºC, 30ºC ó 37º C ( 0,1ºC).
- Matched cuvettes 1,0 cm light path.
- General laboratory equipment.
SAMPLES
Serum or plasma1: Stability 7 days at 2-8ºC, protected from light.
The creatin kinase activity decreases 10% after 1 day at 2-5ºC or after 1
hour at 15-25ºC.
PROCEDURE
1. Assay conditions:
Wavelength: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 340 nm
Cuvette: . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . .1 cm light path
Constant temperature: . . . . . . . . . . . . . . . . . . . . . . 25ºC / 30ºC / 37ºC
2. Adjust the instrument to zero with distilled water or air.
3. Pipette into a cuvette:
4. Mix, incubate for 2 minutes.
5. Read initial absorbance (A) of the sample, start the stopwatch and read
absorbances at 1 minute intervals thereafter for 3 minutes.
6. Calculate the difference between absorbances and the average absorbance
differences per minute ( A/min).
Units: One international unit (IU) is the amount of enzyme that transforms 1 mol
of substrate per minute, in standard conditions. The concentration is expressed
in units per litre of sample (U/L).
QUALITY CONTROL
Control sera are recommended to monitor the performance of assay procedures:
SPINTROL H Normal and Pathologic (Ref. 1002120 and 1002210).
If control values are found outside the defined range, check the instrument,
reagents and technique for problems.
Each laboratory should establish its own Quality Control scheme and corrective
actions if controls do not meet the acceptable tolerances.
