okay, well, no one really wants to hear THIS one, but yes, using serum makes
the odds that an ELISA is accurate MUCH MUCH higher. in fact, as recently as
last november, a famous felv researcher (intials np) stated in a private
note to someone other than myself that an ELISA done on whole blood is
essentially useless. gee, great, this is at the same time that other
"professionals' are trying to assure us that standard,
done-at-the-vet's-office ELISA's (almost ALWAYS done with whole blood) are
highly accurate. i just found out about this about a month ago, and still
haven't digested it and what it means when the real experts (as opposed to
those who just have chosen ignorance) can't agree.

as for the confusion over the IFA being done at the same time as an ELISA,
you're right and wrong, kerry--if it's the FIRST testing, and there has been
no time for the virus to have worked itself out of kitty's system, then yes,
the results will often be the same, based on the same antigenic response.
however, after exposure time has been factored in, the IFA is considered the
confirmatory test. so if you do an ELISA and get a positive, but do a
negative IFA at the same time, cat is considered negative. if you do an
ELISA and get a positive and get a positive IFA at the same time, cat is
considered iffy and still could be testing due to exposure. if you RETEST
and get another positive IFA (most vets don't actually bother doing more
than one ELISA, actually, going straight to the IFA after the first ELISA if
its positive), and more than 120 days from last possible exposure has
occurred, then kitty is considered positive.

the whole, "occult" thing is something that i don't particularly think has
been proven yet--using that as a theory, it means that ANY CAT THAT HAS EVER
positive--and we know that doesn't happen. look at the merck--even it says
that 70% of adult healthy cats don't stay positive--i think that's a
hold-over hypothesis from when it wasn't understood that a NEGATIVE test
doesn' mean anything, either, really--that every cat that could have been
exposed needs to be retested after 120 days, so that the true "occult"
infection time is really the same EXPOSURE time that is involved both in
incubatoin and processing the virus out of the system. the hypothesis of
carriers and hidden, untestable populations made sense back when little was
known, but there is too much evidence for mixed households, and feral
colonies with stable FeLV populations--with little evidence that cats who
suddenly test positive were ever truly negative--remember that all my cats
were originally exposed by a beautiful tortie who most decidedly tested
negative at the shelter before she came home--and died fully positive a
little over a year later. none of the very young, nor the older, frail cats
in the house ever turned positive..... (anny and mysti were 3 months old
when brownee moved in, they're going on nine now, so i guess they COULD be
harboring it occultly......)

um, what was the question again?

Spay & Neuter Your Neighbors!
Maybe That'll Make The Difference....

Special-Needs Coordinator, Purebred Cat Breed Rescue (www.purebredcats.org)
Member, SCAT (Special-Cat Action Team)
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