LBC. pptx

Liquidbasedcytology

1. Liquid Based Cytology Presenter Dr Rohan Guide Dr Kunda Jagdale

2. Introduction Specimens from screening for cervical cancer are conventionally prepared (CP) for cytology by smearing collected cells directly onto a glass slide and then fixing them with alcohol. With liquid-based cytology (LBC), cells that have been stored in preservative fluid are collected and a specimen is prepared from the liquid cytology LBC uses an automated specimen processing system that clearly displays cytologic features of a specimen despite the limitations on the area that can be viewed. Infact countries like UK has switched to LBCs for purpose of screening Some study shows even decrease in inadequate samples from 9.1 % to 1.6%

3. For LBCs we prefer two FDA approved systems Sure Path Centrifugation and sedimentation through a pressure gradient Thin prep Filtration and collection of vaccum packed cells on membrane and transferring to slide These methods of PAP preparation is better since it efficacy than traditional methods are good and also specificity and sensitivity is 90% fro the same

4. Morphology Clean background Cells are shrunken Cytoplasmic and nuclear features are more easily identified Cells with low grade dyskaryosis, especially koilocytosis Lower nuclear hyperchromasia Glandular neoplasms show characteristic picture in thin film cytology

5. SurePath Sample collection is done by using SurePath special kit, which includes a SurePath preservative fluid collection vial and the sampling device

6. Principle of SurePath Works on principle of density gradient

7. The enriched cell pellet is now transferred to settling chamber, further mounted on slide and then staining is done to obtain a smear The image shown is the instrument used to mount the slide while other image shows the mounted slide with help of settling chamber

8. Thin Prep method Cervical sample is collected and rinsed into the Thin prep vial Cells preserved and sent to lab using which smear is prepared

9. Advantages Immediate fixation with enhanced nuclear and cytoplasmic detail All material collected is available for microscopic evaluation A representative sample is prepared for cytological evaluation but multiple samples can be prepared as necessary Clearer background so that epithelial cells of interest are less likely to be obscured A thin layer of dispersed cells are spread over a fixed area so that the area to be screened is small and the preparation takes less time to screen than a conventional smear Unsatisfactory rate decreased LBC samples is suitable for other tests e.g. HPV testing LBC slides are suitable for automated analysis

10. Disadvantages Smear patterns altered because of randomization of cells Abnormal cells are dispersed Scanty LBC preparations can be difficult to screen and interpret Blood mucous inflammation and malignant diathesis are still present but appear slightly different Epithelial cells appear mostly as single cells and are slightly smaller than they appear in conventional smears especially endocervical cells and immature metaplastic cells. LBC is more expensive than conventional test

11. The Bethesda criteria for determination of adequacy of LBC Samples Any specimen with abnormal cells is by definition satisfactory for evaluation A minimum of 5,000 well-visualized/preserved squamous cells should be seen in the slide A minimum of 10 fields should be counted usually at x40 objective along a diameter that includes the center of the preparation. Slides with fewer than 5000 cells should be examined to determine the reason The average cell number per microscopic field to achieve 5000 cells is shown in the following table. If there are hypocellular or empty areas on the preparation the percentage of the hypocellular areas should be estimated

12. LBC modification of cell morphology The main effects of LBC on the morphology of epithelial cells in the samples are : Loss of relationships between cells and random spread of cells Dispersal of abnormal cells Scanty monolayers can be difficult to screen and interpret

13. This how adequate smears will look on LBC while other figure gives us idea that how cells are free and not overlapping hence helping us to know clear morphology of cells in LBCs.