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DISCRETPAK™ REAGENTS - Creatine Kinase (CK)

Intended Use

For IN VITRO diagnostic use in the quantitative determination of Creatine Kinase (CK) in serum using manual or automated applications.

Method Principle

The Creatine Kinase enzyme catalyzes the conversion of Creatine Phosphate and Adenosine Diphosphate to Creatine and ATP. The resultant ATP is quantitatively determined by coupling a hexokinase (HK) reaction and a Glucose-6-phosphate Dehydrogenase (GPDH) reaction to the CK reaction. GPDH catalyzes the oxidation of glucose-6-phosphate to 6-phosphogluconic acid with concomitant reduction of NADP. The amount of NADPH produced is proportional to the CK activity present in the serum sample and its concentration is measured by the increase in absorbance at 340nm. The reaction scheme below illustrates the reactions that occur in this method.

             CK
Creatine phosphate + ADP ────────> Creatine + ATP

HK
                    D-glucose + ATP ────────> ADP + Glucose-6-phosphate

GPDH
            Glucose-6-phos + NADP ────────> 6-phosphogluconate + NADPH


Preparation Of Working Reagents

Catachem Creatine Kinase Working Reagent is prepared by adding the corresponding CK Diluent volume to the CK Reagent container. 

Reagent Storage And Stability

Catachem Creatine Kinase Reagents are stored at 2-8°C. When stored as directed, these reagents are stable until the expiration date stated on the label. Store the Creatine Kinase Working Reagent (liquid) at 2-8°C. When prepared and stored as directed, the Creatine Kinase Working Reagent is
stable for seven days.

Method Performance Characteristics

Sensitivity: 0.00023-0.00028 absorbance units/u/L.
Linear Range: 0-1200 u/L.
Precision: Within-run and day-to-day precision is summarized below:

CK

Within-Run Precision

Total Precision

MEAN

SD

CV

SD

CV

U/L

U/L

%

U/L

%

110

1.7

1.50

2.60

2.40

571

5.7

1.00

12.70

2.20

1014

7.8

0.70

23.00

2.30


Correlation

A comparison of this method using an automated analyzer and a reference method based upon the recommendations of the Scandinavian Committee on Enzymes resulted in the following regression statistics.

Correlation Data

Parameter

Data Observed

N

120

Range (U/L)

24 - 2107

Regression

Y = 0.985x + 3.4

Correlation

  r = 0.999

Sy,x

8.1