low WBC in cats

I took one of my cats for dental cleaning and his pre anesthesia blood panel shows a low WBC. The vet told me it could have been from gingivitis. I have to take him back in 10 days for another blood test. What would be other causes of low WBC?? I'm starting to worry. He's about 4 yrs old and an indoor cat.

[Aleda M Cheng, D.V.M., C.V.A]

Low WBC in cats can be caused by gingivitis especially if the gingivitis is caused by a Viral or Bartonella infection which has caused damage to WBC production in the bone marrow.  Once the infection is cleared the bone marrow can recover.  

Other common causes for low WBC's include viral diseases (FELV, FIV, FIP, Feline Panleukopenia), Inflammatory disease, Cancer's such as Lymphoma, bone marrow disease, or immune mediated disease.

Hopefully your cat has already tested negative for FELV and FIV.  But it might be helpful to have a Bartonella test performed on your cat's blood.  Bartonella can cause gingivitis and upper respiratory infections and requires the antibiotic Zithromax for resolution.

Do take your vet's advice about rechecking your cat's WBC's in a couple of weeks.