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cystocentesis

n. puncture of the bladder (of an animal), through the abdominal wall, in order to obtain a sample of urine

Wikipedia
Cystocentesis

Cystocentesis is a veterinary procedure where a needle is placed into the urinary bladder through the abdomen of an animal and a sample of urine is removed. Diagnostic cystocentesis is used to prevent sample taken for urinalysis from being contaminated with bacteria, cells and debris from the lower urogenital tract. Therapeutic cystocentesis may be employed to relieve pressure buildup due to urethral obstruction. Therapeutic cystocentesis is typically last resort for relief, as a greatly distended bladder is more likely to rupture when punctured. A safer method of emptying the urinary bladder in this condition is by urethral catheterization.