Contamination poses a frequent challenge depending on the method of collection used , thus a cutoff of 105 CFU\/mL is used for a `` clean-catch '' mid stream sample , 104 CFU\/mL is used for catheter-obtained specimens , and 102 CFU\/mL is used for suprapubic aspirations ( a sample drawn directly from the bladder with a needle ) .
Contamination poses a frequent challenge so a cutoff of 105 CFU\/mL is used for a `` clean-catch '' mid-stream sample , 104 CFU\/mL is used for catheter-obtained specimens , and 102 CFU\/mL is used for suprapubic aspirations ( a sample drawn directly from the bladder through the stomach wall with a needle ) .