Method of evaluating hormonal status from vaginal smears
The maturation index (MI) is the most commonly used index for evaluating hormonal status. This involves selecting five random fields (x10 magnification) and counting 100 epithelial cells in each area determining the percentage of superficial intermediate and parabasal cells in each area. The result is expressed as MI = % parabasal cells: % intermediate (navicular) cells: % superficial cells. An MI of 0:100:0 indicates the predominance of intermediate cells for example in pregnancy . An MI of 0: 60:40 is often found in women who are on oral contraceptives. Superficial cells predominance may be found mid cycle, whereas an MI of 90:10:0 can be expected in a post menopausal woman. An MI of say 0:0:100 in a post menopausal woman should be cause for alarm as it may reflect the presence of an oestrogen secreting granulosa cell tumour. Further investigation is warranted providing that an exogenous source of oestrogen such as a cosmetic source has been ruled out.