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DISCRETPAK™ REAGENTS - Alanine Aminotransferase (ALT/SGPT)

Intended Use

For IN VITRO diagnostic use in the determination of ALT in serum using manual or automated applications.

Method Principle

The Alanine Aminotransferase (ALT) enzyme catalyzes the conversion of L-Alanine and α-Ketoglutarate to L-glutamate and Pyruvate. The Pyruvate produced is then quantitatively determined by the LDH-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 ALT enzyme activity in the serum sample. The reaction scheme below illustrates the reactions that occur in this method.

 ALT
             L-Alanine + α-KG ───────> L-Glutamate + Pyruvate

LDH
Pyruvate + NADH ────────> Lactate + NAD


Preparation Of Working Reagent

Catachem ALT Working Reagent is prepared by combining Sample Diluent-R1 (Substrate) with the activator reagent-R2 (Co-factor).

Reagent Storage And Stability

The ALT Liquid Stable reagents are stored at 2-8°C. When stored as directed, the reagents are stable until the expiration date stated on the label. The ALT Working Reagent is stored at 2-8°C. When prepared and stored as directed, the ALT Working Reagent is stable for 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 below:

ALT

Within-Run Precision

Total Precision

MEAN

SD

CV

SD

CV

U/L

U/L

%

U/L

%

32

1.50

4.70

2.00

6.00

384

6.60

1.70

6.60

1.60

728

7.10

1.00

7.40

1.00

 

Correlation

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

Correlation Data

Parameter

Data Observed

N

101

Range

10-397 U/L

Regression

Y = 0.969x + 3.3

Correlation

  r = 0.997

Sy,x

4.5