Comparison of two preparatory techniques for urine cytology.

Abstract

Two methods of preparation of urine for cytology were compared retrospectively. In method 1 cells in the urine were fixed after the preparation of the smear; in method 2 the cells were fixed before smear preparation. Urine cytology reports were correlated with subsequent histological analysis. The specificities of urine cytology using both methods were high (99%). The sensitivity using method 1 was 87%; using method 2 it was 65%. This difference was significant. The cell preparation technique therefore significantly changes the sensitivity of urine cytology. Cellular fixation after smear preparation is preferable to smear preparation after fixation.The importance of urine cytology for the detection of urological malignancy is well established.l" Exfoliated cells in a urine sample, especially single cells, deteriorate rapidly and degenerative changes are seen within one hour.5 To permit optimal visualisation of the sample it is important, therefore, to have a high yield of well preserved cells, and to achieve this a variety of methods have been used."'0This retrospective study compares a method in which the cells are spray fixed after the smear is made with one in which fixation is undertaken before smearing. MethodsAll urine cytology reports for two six month periods were retrieved from the computer based files and compared. In the last six months of 1987 the specimens were fixed after the smear was made (method 1); in the last six months of 1988 the cells were fixed before smear preparation (method 2). The samples were received in an identical manner with that described in method 1. The entire sample was centrifuged at 1500 rpm for five minutes using an MSE Centaur 2 Centrifuge and the supernatant decanted. Fixative (5 ml) (25 ml glacial acetic acid, 20 ml methanol, 105 ml distilled water) was then added to the deposit of cells, mixed well, and allowed to stand for 30 minutes. The sample was respun, the supernatant decanted, and the sample processed in the cytospin (Shandon Cytospin 2) as in method 1. The slides were allowed to dry for two to three minutes and the preparation stained in an identical manner with that described in method 1. When haematuria was suspected, a wet preparation was made to look for red blood cells. CALCULATION OF RESULTSThe cytological diagnoses were correlated with the final histological diagnoses using interlinked computed records. The reports of urine preparations were divided into the following categories: 1 Positive cytology-this was subdivided into two subgroups clearly malignant and suspicious of malignancy. 2 Negative cytology-urine samples where no malignant cells were seen. 3 Inadequate specimen-any specimen in which the preparation was obscured by polymorphs, crystals, bacteria, squames, spermatozoa, or was poorly cellular, or consisted of degenerate cells. ResultsBetween July 1987 and December 1987 a total of 372 urine samples were examined. Of these samples, 297 (80%) were reported as negative, 30 (8%) as inadequate, 17 (5%) were suspicious of malignancy, and 28 (7...

Tracing of “Decoy Cells”: Rapid Screening Test for Demonstration of Active Polyomavirus Infection in Patients with Renal Transplants and Urologic Disorders

“…cells were used (2). After collection they were transported using IsoTherm System (Eppendorf, Germany) to the laboratory and were immediately processed for the preparation of glass-slide smears.…”

A comparative Between Different Urine Fixation Methods for Cytological Examination

“…Previous studies have two methods of preparation of urine for cytology were compared retrospectively In method 1 cells in the urine were fixed after the preparation of the smear; in method 2 the cells were fixed before smear preparation. Cellular fixation after smear preparation is preferable to smear 3 preparation after fixation (Dhundee and Rigby, 1990). Mygind, et al in (1987) they found Espostis fixative resulted in a good preservation for cytological examination and formalaldehyde or 10% isopropanole were poorly preserved (Mygind and Lauritzen, 1987).…”