Introduction Screening test can detect squamous dysplasia and cancer can evaluate patient's sex hormones superficial squamous cells indicates full mucosal surface maturation and therefore the presence of estrogen high estrogen without progesterone results in 100% superficial squamous cells intermediate squamous cells indicates presence of progesterone high progesterone in pregnancy results in 100% intermediate cells parabasal cells indicates lack of estrogen and progesterone seen in elderly women Process must sample transition zone between endo (columnar) and exo (squamous) cervix smear must show presence of columnar cells to prove that transition zone was reached