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VETSPEC™REAGENTS - Urea Nitrogen (BUN)

Intended Use

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

Method Principle

The enzyme Urease hydrolyzes Urea to Ammonia and Carbon Dioxide. The Ammonia produced is quantitatively determined by the GLDH-NADH reaction. The decrease in absorbance due to the oxidation of NADH to NAD is monitored at 340 nm. The reaction scheme below illustrates the reactions that occur in this method:

Urease
  Urea + H2O ────────> 2NH3 + CO2

GLDH
          NH3 + α-KG + NADH ────────> L-glutamate + NAD + H2O

 

Preparation Of Working Reagent

Catachem Urea Nitrogen reagent is formulated as liquid ready-to-use. No preparation is required.

Reagent Storage And Stability

Catachem Urea Nitrogen liquid reagent is stored at 2-8°C. When stored as directed, this reagent is stable until the expiration date stated on the label. The Urea Nitrogen Working Reagent is stored at 2-8°C. When prepared and stored as directed, the Urea Nitrogen Working Reagent is stable for 60 days.

Method Performance Characteristics

Sensitivity: 0.0016 - 0.0024 absorbance units/mg/dL.
Linear Range: 0-200 mg/dL.
Precision: Within-run and day-to-day precision is summarized below.

BUN

Within-Run Precision

Total Precision

MEAN

SD

CV

SD

CV

mg/dL

mg/dL

%

mg/dL

%

6

0.40

0.49

0.49

9.10

58

1.35

1.35

1.35

2.30

117

0.75

1.34

1.34

1.25

 

Correlation

A comparison of this method using an automated analyzer was carried out against a reference method based on the procedure of Talke and Schubert resulted in the following regression statistics:

Correlation Data

Parameter

Data Observed

N

100

Range (mg/dL)

4-150

Regression

Y = 1.0025x + 0.38

Correlation

r = 0.994

Sy,x

3.90