You're speaking with Dr. Michael Salkin. Welcome to JustAnswer. I'm currently typing up my reply.
It's a moderately low white blood cell count. The normal range is 7.3 - 18.6. We can see more specifically why your cat's white blood cell count is low by looking at the number of each white blood cell individually. Can you upload a copy of all of his test results to our conversation? I understand that you might not have a copy at home but his vet can give you one which you can scan into your computer and then give me the file link or you can photograph the pages and upload them by using the paperclip icon (if you can see that icon) or by using an external app such as dropbox.com/