Rat Vaginal Impedance Checker

  • The best method to know proestrus stage
  • Powerful tool for the improvement of reproduction efficiency
  • Simple operation
  • Battery-operated

MK-12-B Rat Vaginal Impedance Checker has been designed to obtain a precise information on optimum day for mating during estrous cycle in the rats.

The electrical impedance of the epithelial cell layer of vaginal mucosa is measured at the frequency of 1 kHz by insertion of the probe into vagina. In the proestrus stage significantly high impedance is produced compared to that in the other stages of the estrous cycle. 3 kohm of impedance can be considered a standard indicating proestrus stage. Measuring range is 0 – 19.9kohm.

The conventional method known as vaginal smear method takes troublesome procedures such as taking smear, drying, dying and check-up using microscope. It really takes skill as well as time and labor.

Rat Vaginal Impedance Checker is a time & labor saving device on top of high reliability. Further, operation is so simple that even inexperienced personnel can easily use it.

NOTE: This product has been developed in cooperation with Chugai Pharmaceutical Co., Ltd.

mk11F1P: Proestrus

mk11F2∆: Changes of EIV during estrus cycle in the rats. EIV shows high value at proestrus stage and periodical alteration concurrently with estrus cycle

M. Koto (1987), Exp. Anim., 36(2), 195-198


The continuous use of the MK-12-B Rat Vaginal Impedance Checker does not affect pregnancy rate or other reproduction achievements.


  • Bartos, L.(1975). Physiol. Bohemoslov., 24,427.
  • Bartos, L.(1977). Lab. Anim., 11,53-55
  • Bartos, L.(1977). Lab. Anim., 11,57-58
  • M..Koto(1987). Exp. Anim., 36(2),151-156.
  • M..Koto(1987). Exp. Anim., 36(2),195-198
  • Teradach,C.(1982). Sci. Tech. Anim. Lab.,7,49-84

The Standard System Includes:

  • MK-12-B Main Unit – 1
  • RP-45A Rat Probe – 1
  • CA-100A Cable – 1
  • Rechargeable Battery (Ni-MH) – 4


Measurement Range0 - 19.9 Kohm
Accuracy(+)(-) 1 % (+)(-) 1 digit
Battery 2 Rechargeable Battery (Ni-MH)
Battery Life42 hours (When used continuously)
DimensionsW96 x D145 x H25 mm
WeightApprox. 180 g (Battery excluded)


RP-45B Rat Probe L55 x O.D.4.5 mm
MP-35A Mouse Probe L50 x O.D.3.5 mm

IMPORTANT NOTICE: The MK-12-B has been developed exclusively for rats. A mouse probe is available upon request, but test results cannnot be guaranteed.

Need more probes or cables?

The cables required vary depending on the version of the device, especially the main body and the probe.
Please check the connectors on both the device and the probe, and specify Type A or Type B when purchasing new cables.

Specifications are subject to change without notice.