Pap Class systemReagen (WHO classification)Rucha classificationBethesda classificationClass 1Negative for malignantNegativeWithin normal limitClass 2Inflammation/squamous atypia/koilcytes-Atypical squamous cells of unknown significance(ASCUS)Class 3Mild dysplasia(1/3rd of sample)CIN1LSILClass 4Moderate dysplasia(1/3rd to 2/3rd of sample)Severe dysplasia(>2/3rd of sample)Carcinoma insituCIN2,3HSILClass 5Invasive cancerInvasive cancerInvasive cancerPap smear is only a screening test. Any abnormality encountered in it should be confirmed by colposcopic biopsy.Features of abnormal pap cytology*Mosaicism*Punctuations*Abnormal dense nuclei*Granular cytoplasmIndications for colposcopy biopsy*Non visualization of the transformation zone*Obvious fungation in transformation zone*Mismatch between colposcopy and pap smear*Stage IA-1(microinvasive)Refer: Shaw&;s Textbook of Gynaecology, 15th edition, pg no: 402, 405