Question

Which of the following compromises the reliability of urinary urea nitrogen to calculate nitrogen balance?

1: Protein intake <0.5 g/kg/day
2: Creatinine clearance <50 mL/min
3: Diuresis >2.5 L
4: Fecal nitrogen >1g

Answer 1

Protein intake, creatinine clearance, diuresis, and fecal nitrogen can all compromise the reliability of urinary urea nitrogen in calculating nitrogen balance.

Step-by-step explanation:

The reliability of urinary urea nitrogen to calculate nitrogen balance can be compromised by several factors.

1. Protein intake less than 0.5 g/kg/day can lower urea output, affecting the accuracy of urinary urea nitrogen as a measure of nitrogen balance.
2. Creatinine clearance less than 50 mL/min can indicate impaired kidney function, which may affect the filtration and excretion of urea, leading to unreliable results.
3. Diuresis greater than 2.5 L can dilute the concentration of urea in urine, making it difficult to accurately assess nitrogen balance.
4. Fecal nitrogen greater than 1g indicates nitrogen losses through the gastrointestinal tract, which may not be reflected in urinary urea nitrogen measurements.