Anemia? PCV/hematocrit test questions!

Hi, this is only my second post but I'm already back.

Sabby, my 7 m/o FeLV+ kitten has an appointment tomorrow as I want to see if he is anemic. The past few days it looks like he is breathing harder, so I'm a little worried. 

I'm going to ask for a PCV test if the vet is concerned but doesn't offer one. How long did your cat's PCV/hematocrit test take both to collect the blood from him, and for them to tell you the results?

Thank you.

I'm hoping he is okay, but I just want to be sure. 

Most vets can run the hematocrit in-house. Ours always drew enough blood to send out as well. This took only a few minutes, as does running the hematocrit.