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DISCRETPAK™ REAGENTS - γ-Glutamyl Transpeptidase (γ-GT)

Intended Use

For IN VITRO diagnostic use in the quantitative determination of γ-Glutamyl Transpeptidase (γ-GT) in serum using manual or automated applications.

Method Principle

Gamma Glutamyltransferase transfers the Gamma Glutamyl group from the substrate Gamma Glutamyl-p-nitroanilide (GNA) which has maximum absorbance at 405 nm. The rate of increase in absorbance is directly proportional to the GGT enzyme activity in the serum sample. The reaction scheme below illustrates the reaction that occurs in this method.

GGT
L-γ-Glutamyl-p-nitroanilide + Glycylglycine ──────> L-γ-Glutamyl-glycylglycine + p-nitroanilide


Preparation Of Working Reagents

Catachem γ-GT Working Reagent is prepared by adding the required volume of distilled or deionized water as indicated on the label, to the required number of vials of γ-GT Reagent. 

Reagent Storage And Stability

Catachem γ-GT Reagent is stored at 2-8°C. When stored as directed, the reagent is stable until the expiration date stated on the label. The γ-GT Working Reagent is stored at 2-8°C. When prepared and stored as directed, the γ-GT  Working Reagent  is stable for ninety days.

Method Performance Characteristics

Sensitivity:  0.00085 - 0.0015 absorbance units/U/L.
Linear Range: 0-1000 U/L
Precision: Within-run and day-to-day precision is summarized below:

γ-GT

Within-Run Precision

Total Precision

MEAN

SD

CV

SD

CV

U/L

U/L

%

U/L

%

49

1.30

2.50

2.70

5.60

270

2.30

0.90

2.70

1.00

484

1.90

0.40

4.40

0.90


Correlation

A comparison of this method using an automated analyzer and a referenced procedure resulted in the following regression statistics.

Correlation Data

Parameter

Data Observed

N

208

Range (U/L)

49-484

Regression

Y = 1.002x + 4.0

Correlation

  r = 0.999

Sy,x

3.60