What method of urine sample collection would not be associated with traumatic hematuria?

• A. Catheterization
• B. Manual expression
• C. Cystocentesis
• D. Free catch

Answer: (D)

The main idea here is avoiding injury to the urinary tract during sample collection. Traumatic hematuria happens when the mucosa or walls of the urinary tract are irritated or injured during collection. Free catch simply lets the animal void urine and then collects it; there is no instrumentation or manipulation of the urinary tract, so it carries the lowest risk of causing trauma and, thus, traumatic blood in the urine.

In contrast, inserting a catheter through the urethra (catheterization) can irritate or lacerate the urethral or bladder mucosa. Forcing or squeezing to express urine externally (manual expression) can compress and injure the bladder or urethra. Puncturing the bladder with a needle during cystocentesis, while often giving a clean sample, involves penetrating tissue and can cause some localized bleeding at the puncture site. So the method that would not be associated with traumatic hematuria is free catch.