Study on sample preparation for urine cytology

Abstract

Objective: To determine optimal sample preparation for cellular yield in urine cytology without special apparatus.
Study design: Eighty voided urine specimens from 38 patients with histologically confirmed G2/G3 urothelial carcinoma were prepared three ways:(1) dipping fixation in which smears made from the centrifuge sediment were put into 95% ethanol before drying;(2) spray fixation, in which a fixative was sprayed onto the wet smear; and (3) modified two-step fixation, in which centrifuge sediment was treated twice with alcoholic carbowax fixatives before smears were prepared. All smears were stained by the Papanicolaou method and studied for cellular yield. Cell yield was divided into 5 grades based on the number of diagnostic cancer cells:(-)(cell number, 0), (1+)(1 to 10), (2+)(11 to 50), (3+)(51 to 200), (4+)(201 or more).
Results: Modified two-step fixation enhanced cellular yieldcomparedto other methods. Cell yields for (-), (1+), (2+), (3+), and (4+) in dipping fixation numbered 16 (20.0%), 19, 16, 10, and19 samples. Those in spray fixation numbered 6 (7.5%), 13, 20, 15, and 26 samples. Those in modified two-step fixation numbered 1 (1.3%), 15, 22, 11, and 31 samples.
Conclusion: Modified two-step fixation yielded more diagnosticcancer cells than other methods.