Pcr or quick test for FELV / FIP prior to annual vax?

Hi. Happy new year to all. I’m writing after months in hopes of advice as vita schnitzel is due for annual vaccinations. In South America and I’m aware in the uk all is different but I’d be grateful for advice if possible. The pcr takes 20 days to get back and I’ve never understood how it compares to the quick test other than I’m aware that her long ago quick test was done too soon to be definitive. I can just get her vaccinated and believe vaccinations are available 3/4 weeks apart this year,she turned 1 last month. I would like to do things as logically and responsibly as possible and will find a local vet to consult ideally but always benefit from any and all input. Thanks so much!

Sorry I think I messed up acronyms- whichever one I can get vaxes for - last years were not ideally scheduled though happy her fractured tibia healed itself post -her removing her second cast. Just asking generally even if much lower rates if you like testing for the two vaxable ones pre-vax sorry thanks so much

Hello Here is a blog about Feline Leukaemia, FeLV, assuming that  this is the disease in question. https://vethelpdirect.com/vetblog/2021/01/20/do-cats-need-leukaemia-vaccines/ If a cat already has FeLV at the time of vaccination, then the vaccination won't be effective.  Furthermore, because there are different types of vaccination on the market, I would recommend that your vet either contacts a representative from the vaccine company, or refers to the data-sheet (a peice of paper that is compulsorarily issued with drugs in the uk, loaded with safety information), to check whether vaccinating your cat is the correct thing to do in your cats' specific circumstances.  A lot of vets do reccommend testing a cat of unknown status prior to the vaccination in order to avoid an unnecessary vaccine.  The snap-test is quick and, although less reliable, the answer is available immediately.  However, false positives can happen - and recently infected cats can read positive for a while and then clear - so later verifying that test is frequently reccommended. You can get both false positives and false negatives with FeLV tests; no system is perfect.  The International Cat Care Website has a good article about this, available for a domation.