What is the minimum amount of urine a nurse should withdraw for a urine culture from an indwelling catheter?

The minimum amount of urine that a nurse should withdraw from an indwelling catheter for a urine culture is typically 3 to 5 mL. This volume is sufficient to provide an adequate sample for laboratory analysis while minimizing any potential for contamination. It ensures that the culture can accurately reflect the presence of bacteria or other pathogens in the urine.

Using a smaller sample, such as 1 to 2 mL, may not yield reliable results due to the possibility of inadequate volume for bacterial growth or insufficient representation of the bladder urine. Similarly, withdrawing too much urine, like in the 10 to 15 mL range, is unnecessary and could increase the risk of introducing contaminants, influencing the culture outcomes. The standard practice of collecting 3 to 5 mL helps to balance sufficient quantity with the integrity of the sample for diagnostic purposes.