• Assay Type Detection Kit
  • Sample Types Serum, Plasma, Urine, Saliva
  • Sensitivity 30 µg/dL
  • Species Human
  • Assay Duration 30 Minutes
  • Samples/Plate 40 in Duplicate
  • Readout Colorimetric, 450 nm
  • Standard Curve
  • Description

    Assay Principle: 

    The Urea Nitrogen (BUN) Detection Kit quantitatively measures urea nitrogen in serum, plasma, urine, and saliva. Please read the complete kit insert before performing this assay. The Urea Nitrogen (BUN) Detection Kit can be completed in 30 minutes. 

    Use our provided urea nitrogen standard to generate a standard curve for the assay. Pipette the standards or diluted samples into a transparent microtiter plate, along with Color Reagents A and B. We recommend a 30-minute incubation shaking at room temperature, and after 30 minutes, use a plate reader at 450nm to detect the resulting signal. Use the recorded intensity and the standard curve to calculate the urea nitrogen concentration in the samples. 


    Urea is a by-product of protein metabolism by the liver and is removed from the blood by the kidneys. Urea freely filters through the glomerulus but is reabsorbed by the renal tubules in a flow-dependent fashion. A higher flow rate causes more urea nitrogen to be cleared from the circulation and eliminated through the kidneys. As a result, the level of circulating urea nitrogen and serum creatinine serves as a primary measure of kidney function.

    Average adult blood urea nitrogen (BUN) levels should be between 7 and 21 mg urea nitrogen per 100 mL blood (mg/dL). Azotemia, poor kidney function, will cause elevated BUN levels (≥ 50 mg/dL) and is associated with acute kidney failure or injury, severe acute pancreatitis, congestive heart failure, or gastrointestinal bleeding. Azotemia also can occur with dehydration, as a result of alcohol abuse, or with high protein diets. Lower than expected BUN levels are usually not clinically predictive but are primarily associated with liver disease or malnutrition, including malabsorption and low protein diets. Urine and saliva are acceptable non-invasive samples for the measurement of urea nitrogen.