THE ACCURACY OF LIQUID BASE PAP SMEAR VS CONVENTIONAL PAP SMEAR CYTOLOGY

Abstract

The main aim of the present study was to assess the diagnostic accuracy of Liquid base versus Conventional smears (CS). The specific objective was to evaluate and compare efficacy liquid base cytology with conventional cytology (CS) as a screening tool and to assess the quality of immunohistochemical stain in conventional smears. A prospective study including 100 cervical samples over a period of six month. Split sample was obtained using cervex-brush. CS was prepared from the brush and the brush head was suspended in the LBC vial and processed by thin prep 5000 machine. The smears were stained with Pap stain and extra five conventional and thin prep slides prepared and stained with immunomarker. Results showed that there were 4.0% unsatisfactory (U/S) cases in CS and 1.0% in LBC; the main cause was ranging between obscuring blood and inflammation in CS and low squamous cellularity in LBC. About 5% split samples had epithelial abnormalities both in CS and LBC (3% atypical squamous cells of undetermined significance (ASCUS), devided between LBS 2% while CS1%.Low grade squamous intraepithelial lesion (LSIL) 2%, devided between LBC 1% and CS 1%. Infections as Trichomonas vaginalis (TV) and spores of candida species, 1% and 2% respectively detected only in LBC smear and missed in CS preparations of the same samples, considering 2-3 minutes for LBC screening and 5-6 minutes for CS screening following the international standards. Conventional smears did not appear to confer a cytomorphological advantage and has a lower diagnostic accuracy using IHC. The sensitivity of Thin Prep was significantly higher than that of CS due to cellular clumps and presence of marked inflammatory cells and blood which compete other epithelial cellular elements in staining affinity in addition to the length of the smear which need large volume of stains to cover the whole area. While the confined area of thin prep smear and homogenous cellular distribution support the advantages of thin prep over the conventional smear when using IHC stain. The study concluded that LBC technique leads to significant reduction of U/S rate. LBC samples offered better clarity, uniform spread of smears, less time for screening and better handling of hemorrhagic and inflammatory samples. In addition to feasibility to do further special stains and HPV tests. LBC had equivalent sensitivity and specificity to CS.