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VETSPEC™REAGENTS - Lactate Dehydrogenase (LD)

Intended Use

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

Method Principle

Lactate Dehydrogenase (EC 1.1.1.27; L-lactate: NAD oxido reductase) is an enzyme which catalyzes the oxidation of L-Lactate to Pyruvate with the mediation of NAD as a hydrogen acceptor. The reaction is reversible and strongly favors the conversion of Pyruvate to L-Lactate. The rate of increase in absorbance of the reaction mixture due to the formation of NADH is proportional to the LD concentration present in the serum sample. The reaction scheme illustrates the reaction that occurs in this method.

LD
            L-Lactate + NAD ────────> Pyruvate + NADH + H+


Preparation Of Working Reagents

Catachem LD Working Reagent is prepared by combining LD Substrate Reagent-R1 with the NAD reagent-R2.

LD Reagent Storage And Stability

Catachem LD liquid reagents are stored at 2-8°C. When stored as directed, this reagent are stable until the expiration date stated on the label. Catachem LD Working Reagent is stored at 2-8°C. When prepared and stored as directed, the LD Working Reagent is stable for 8 days. If stored at room temperature, the reagent is stable for eight hours.

Method Performance Characteristics

Sensitivity: The sensitivity of this method is 0.0002 absorbance units per u/L.
Linear Range: No significant nonlinearity over the range of 0-600 u/L.
Precision: Within-Run and Day-Day (Total) precision is summarized below:

LD

Within-Run Precision

Total Precision

MEAN

SD

CV

SD

CV

U/L

U/L

%

U/L

%

61

1.20

1.80

0.90

1.40

391

2.90

0.90

3.40

1.20

546

3.70

0.60

5.70

1.00


Correlation

A comparison of Catachem LD method using an automated analyzer was carried out against a reference LD procedure based upon the lactate to pyruvate reaction. The following regression statistics were observed:

Correlation Data

Parameter

Data Observed

N

123

Range (U/L)

100-431

Regression

Y = 0.999x + 0.08

Correlation

  r = 0.999

Sy,x

3.70