Which combination of findings best defines azotemia?

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

Answer: (C)

Azotemia is a buildup of nitrogen-containing waste in the blood caused by reduced kidney filtration. The two main markers are urea (produced in the liver) and creatinine (a byproduct of muscle metabolism). When the kidneys aren’t filtering well, both wastes accumulate, so you see elevations in both urea and creatinine, which strongly points to impaired glomerular filtration. Urea alone can rise for non-renal reasons such as high protein intake, liver function, or hydration status, while creatinine can be influenced by muscle mass and other factors. Therefore, the combination of increases in both markers most reliably indicates azotemia due to kidney dysfunction. Decreased levels of these waste products would not indicate azotemia.