Azotemia is defined by increased levels of which substances?

• A. Increased urea
• B. Increased creatinine and urea
• C. Decreased creatinine
• D. Increased creatinine

Answer: (B)

Azotemia reflects a buildup of nitrogenous waste in the blood due to reduced kidney filtration. The two main waste products we track are urea and creatinine, both of which rise when the glomerular filtration rate falls. Because azotemia signals impaired filtration, the strongest definition is when both urea and creatinine are elevated, indicating a consistent rise in nitrogenous waste from diminished kidney function. Decreased creatinine would not indicate azotemia, and while creatinine or urea can rise individually in certain situations, the classic, most comprehensive marker is the simultaneous increase of both substances.