An indirect indicator of blood levels of estrogen based on the proportion of various types of vaginal epithelial cells found in a Pap smear. It is thought that there should be about 5% parabasal cells (newly formed cells), 15% of intermediate (older cells), and 80% superficial cells (dead cells) if the estrogen level is adequate. If higher proportions of parabasal cells (10%) are seen, it is assumed that less estrogen is being produced. This method is quite unreliable as the scraping may not pick up a representative batch of cells.