The unit used to express the total microbial count in dialysate water is?

• A. EU/mL
• B. mg/L
• C. pH unit
• D. CFU/mL

Answer: (D)

Counting microbes in dialysate water is reported as colony-forming units per milliliter, CFU/mL. This unit comes from plating a sample and counting colonies that arise from viable microorganisms; it reflects how many living organisms could multiply in a given volume, which is exactly what we need to assess water quality for dialysis. Other options measure different things: EU/mL is for endotoxin content, not total microbes; mg/L is a chemical concentration; pH unit measures acidity. Therefore CFU/mL is the appropriate unit for total microbial count in dialysate water.