How is urea concentration calculated from Blood Urea Nitrogen (BUN)?

To determine the concentration of urea from Blood Urea Nitrogen (BUN), the conversion factor used is 2.14. This relationship arises because BUN measures the nitrogen component of urea, and urea is composed of two nitrogen atoms per molecule but also includes carbon and oxygen atoms.

When BUN is measured, it reflects the amount of nitrogen in the blood, specifically the nitrogen derived from urea. To convert this nitrogen measurement to a total urea concentration, you multiply BUN by 2.14. This calculation effectively translates the nitrogen content into the full urea content because urea's molecular weight gives rise to this conversion factor.

Thus, the correct method for calculating urea concentration from BUN is to multiply the BUN value by 2.14, making option C the appropriate choice.