It's a typo, correct term is resistivo.
Here at page 36, under "Metodo RF/DC"
...Sappiamo che nel metodo resistivo gli impulsi di rivelazione sono correlati al volume cellulare... https://docplayer.it/15417549-Universita-degli-studi-di-fire...

...si evidenzia che solo il metodo resistivo HORIBA non dà differenze analitiche statisticamente significative... https://www.sipmel.it/en/riviste/articolopdf.php/2562

https://en.wikipedia.org/wiki/Coulter_counter

For resistive (method):
Here in the article "The particle size distribution"
...As the resistive method is sensitive to the particle volume... https://www.sciencedirect.com/topics/earth-and-planetary-sci...

https://books.google.com.mx/books?id=a5fvDAAAQBAJ&pg=PA690&l...

For electrical resistance (method):
...The electrical resistance method applies [omissis] and enables measurement of the types of blood cells and their numbers... https://www.sysmex.co.jp/en/rd/history_awards/history/histor...

https://books.google.com.mx/books?id=AreXBAAAQBAJ&pg=PA257&l...

Personally, I would go for Coulter (method):
...As each cell passes through the aperture, it momentarily increases the resistance of the electrical path between the submerged electrodes on either side of the aperture. This causes a measurable electronic pulse... https://wwwn.cdc.gov/nchs/data/nhanes/2013-2014/labmethods/C...

...The Coulter method of sizing and counting particles is based on measurable changes in electrical impedance... http://www.cyto.purdue.edu/cdroms/cyto2/6/coulter/ss000103.h...

...convenience of the Coulter method for counting erythrocytes... https://journals.sagepub.com/doi/full/10.1016/s1535-5535-03-...

...The Beckman Coulter method of sizing and counting particles uses measurable changes in electrical resistance... https://idph.iowa.gov/Portals/1/Files/IMMTB/Complete Blood C...