Specimen collection for Cytology of urine

Specimen collection technique:

• Voided urine
• Ileal conduit urine
• Catheter urine
• Bladder washing
• Upper urinary tract brush cytology

Voided urine

• It is the most common sample type
• Voided urine undergoes degeneration very quickly hence preservative are used to reduce cellular degeneration and stopping bacterial growth.
• Voided urine should be obtained 3 to 4 hours after the patient has last urinated.
• First morning voided urine specimens should be avoided because stagnant cells in the low acid-base balance (pH) and hypertonic environment undergo degenerative changes, making cytologic assessment difficult.
• The minimum amount of urine necessary to ensure adequate cellularity is unknown, but it may be as high as 25 to 100 mL.
• In women, voided urine can be contaminated by vaginal cells, so to ensure the adequacy of the sample, a midstream (“clean catch”) specimen is recommended.

Ileal conduit urine

• This specimen type is useful for follow up of patient who have been treated for bladder cancer.
• An ileal conduit is a urinary diversion that is constructed from a section of ileum when a patient has had their bladder removed during surgery for bladder cancer.
•These patients’ urine samples include a wide range of appearances, including a considerable number of degenerating interstitial epithelial cells, macrophages, inflammatory cells, and mucus..

Catheter urine

• A urinary catheter is short plastic tubing that is inserted into the bladder to allow urine to drain freely into a bag.
• Catheterization carries a risk of urinary tract infection
•Urine from an indwelling catheter is often a pooled sample that has been at room temperature for many hours, and cellular degeneration can be noticeable.

Bladder washing

• Bladder washing is not a common source of urine sample as the procedure is invasive.
• It involves injecting 50-100 ml of saline through a catheter and aspirating fluid before collection.
• The benefits of bladder washings over voided urine include higher cellular preservation, greater cellularity, and a lower risk of background particle contamination.

Upper urinary tract brush cytology

•Direct washings, brushings, or biopsies of a ureter or renal pelvis lesion should be done when an upper urinary tract malignancy is suspected.
•A fine brush is passed into the ureter under endoscopy and X-ray guidance. The brush is pushed back and forth to dislodge the cell after it has been passed into the suspicious area.
•These cells adhere to bristle of brush and can be spread onto a slide.

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