Your cat's vet may utilize a couple of diagnostic methods to check for microsporum canis, including black - light inspection, or, more reliably, skin and hair cultures. (catster.com)
Ringworm can be difficult to diagnose in cats, because the vast majority of healthy adult cats develop an immunity to the primary culprit, a fungus called microsporum canis. (catster.com)
It should be noted that microsporum gypseum and trichophyton mentagrophytes do not glow under the fluorescent light, so this method does not completely rule out a ringworm infection. (wagwalking.com)