Electrical impedance of the epithelial cell layer of vaginal mucosa is measured at the frequency of 1 kHz by insertion of the probe into the vagina
In the proestrus stage significantly higher impedance is produced compared to that in the other stages of the estrous cycle
3 kohm of impedance can be considered a standard for indicating proestrus stage
Measuring range is 0 to 19.9 kohm Ideal alternative to the conventional method (vaginal smear method) that can be a troublesome procedure requiring skill, time and labor