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DISCRETPAK™ REAGENTS - Aspartate Aminotransferase (AST/SGOT)

Intended Use

For IN VITRO diagnostic use in the quantitative determination of AST (SGOT) in serum or plasma using manual or automated applications.

Method Principle

The Aspartate Aminotransferase (AST) enzyme catalyzes the conversion of alpha-Ketoglutarate and L-Aspartate to L-Glutamate and Oxalacetate. The Oxalacetate produced is then quantitatively determined by the MDH-NADH reaction. The decrease in absorbance due to the oxidation of NADH to NAD is monitored at 340 nm. The rate of decrease in absorbance of the reaction mixture is directly proportional to the AST enzyme activity in the serum sample. The reaction scheme below illustrates the reactions that occur in this method.

AST
L-Aspartate + alpha-KG ────────> L-Glutamate + Oxalacetate

MDH
Oxalacetate + NADH ────────> L-Malate + NAD

 

Preparation Of Working Reagent

Prepare Catachem AST Working Reagent by combining Sample Diluent Reagent-R1 (Substrate) with the Activator Reagent-R2 (Cofactor)

AST Reagent Storage And Stability

The AST Liquid Stable Reagents are stored at 2-8°C. When stored as directed, these reagents are stable until the  expiration date stated on the label. The AST Working Reagent (liquid) is stored at 2-8°C. When prepared and stored as directed, the AST Working Reagent is stable for sixty (60) days.

Method Performance Characteristics

Sensitivity: The sensitivity of this method is 0.0002 absorbance units per u/L.
Linear Range: In this method there is no significant nonlinearity over the range of 0-1000 u/L.
Precision: Within-run and day-to-day precision is summarized on next page.

AST

Within-Run Precision

Total Precision

MEAN

SD

CV

SD

CV

U/L

U/L

%

U/L

%

32

0.80

2.70

1.80

5.40

385

4.90

1.30

8.20

2.10

732

3.30

0.50

15.0

2.10

 

Correlation

A comparison of this method using a discrete random access analyzer and a reference procedure based upon the recommendations of IFCC resulted in the following regression statistics:

Correlation Data

Parameter

Data Observed

N

126

Range

15-440 U/L

Regression

Y = 0.994x + 0.95

Correlation

  r = 0.999

Sy,x

3.4