A urinalysis challenge: Answer 4c
4 c — Correct!
Detection of white blood cell casts is reliable evidence of tubular involvement in the infectious inflammatory process. However, concurrent involvement of other portions of the urinary tract cannot be excluded. Detection of numerous bacterial cocci in a fresh urine sample collected by cystocentesis indicates that at least 100,000 bacteria/ml of urine are present, so the bacteriuria is unlikely to represent contamination.