BUN 250

Urea is hydrolysed to ammonia and carbondioxide by urease. Ammonia produced reacts with a-ketoglutarate to form glutamate in presence of glutamate dehydrogenase. NADH is oxidised to NAD in this reaction, which is measured as decrease in absorbance at 340 nm. The rate of decrease in absorbance at 340 nm. is directly proportional to BUN concentration in the specimen. 

Urea + H,O- 2nH, + CO,

GLDH

NH, + a-ketoglutarate + NADH -glutamate + NAD

Abbreviations

GLDH - Glutamate dehydrogenase 

REAGENT STORAGE & STABILITY

• The reagent kit should be stored at 2 - 8 C and is stable till the expiry date indicated on the label. 
• R, and R, reagents are stable till expiry at 2 - 8C.
• The working solution (4 R, + 1 R,) is stable for 30 days at 2 - 8 C. 

• Prewarm at 25Degree  C / 30 Degree  C the required amount of working solution before use. Perform the assay as given below : Working solution: 1.0 mi (800 U1 R, + 200 LI R,) Mix and aspirate. After the initial delay of 30 seconds, record the absorbance of the test at an interval of 30 seconds at 340 nm.
• Determine the change in absorbance ( A Abs.) and calculate test result. 
• Serum / Plasma

Expected Values 

• Urea Nitrogen (BUN) : 5-21 mg/dl
• Expected range varies from population to population. It is therefore recommended that each laboratory should establish its own normal range.