Here's how my vet friend explained things to me which will clarify a little about what Beth is saying about the IFA test.
The IFA test looks to see if the virus is in the white blood cells. It's not a bone marrow test however, white blood cells are produced in the bone marrow, so if the virus is in the white blood cells then it's because it's replicating in the bone marrow. If it's not replicating in the bone marrow the FeLV virus could still be in the bone marrow but dormant. You wouldn't know that without a bone marrow test because it's just sitting there not doing anything and not spreading or causing problems. So here's what the vet has told me about the all ways of testing: The first screening test is the ELISA test. The ELISA test can be performed two ways. It can be done using a snap test kit in the vet's office or the blood sample can be sent to a lab where they do a "Well test." The well test is also an ELISA test that looks for small fragments of the virus in the bloodstream but just done a different way and uses a much larger blood sample. The ELISA test that is done with a snap test kit in the vet's office is also called a combo test because it looks for FIV also. Then there is the 3 way snap test kit which looks for FIV, FeLV and heartworms. I think the ELISA test that is done in a well by sending the blood to a lab just looks for FeLV, not the other two. I'm not positive though. So, the ELISA test looks to see if there are small fragments of the virus in the blood stream. Part of the virus could be in the bloodstream but not in the white blood cells. It gets into the oral cavities and bloodstream before it goes into the bone marrow. When it gets into the bone marrow it could start replicating and then it gets into the white blood cells. The IFA test looks to see if the virus is in the white blood cells. So from my understanding, the virus has to progress from the bloodstream into the bone marrow and replicate like Beth is saying to get into the white blood cells. Usually once it's starts replicating in the bone marrow and getting into the white blood cells the cat will not be able to fight off the virus. FYI - my vet has also said that the 3 way snap test kits don't seem to be as reliable as the combo snap test kit. So that's a very simple and basic way of explaining the different ways of testing and what they look at to determine what stage the virus is in as it spreads throughout the body. That's my understanding and I hope it's correct. Date: Wed, 7 Dec 2011 08:12:39 -0800 From: create_me_...@yahoo.com To: felvtalk@felineleukemia.org Subject: Re: [Felvtalk] Very Scary Testing results! The IFA tests weather the virus is replicating in the bone marrow. You can have a positive SNAP & a negative IFA. This does NOT mean the cat is negative. It just means the virus is not replicating in the bone marrow. Any test can be done wrong & labs can mix up donors with specimins. It happens with humans, it can certainly happen in our pets. Don't Litter, Fix Your Critter! www.Furkids.org From: GRAS <g...@optonline.net> To: felvtalk@felineleukemia.org Sent: Wednesday, December 7, 2011 9:21 AM Subject: Re: [Felvtalk] Very Scary Testing results! The IFA is not testing the bone marrow, though....that would be yet another test. -----Original Message----- From: felvtalk-boun...@felineleukemia.org [mailto:felvtalk-boun...@felineleukemia.org] On Behalf Of Beth Sent: Tuesday, December 06, 2011 9:57 PM To: felvtalk@felineleukemia.org Subject: Re: [Felvtalk] Very Scary Testing results! It is possible the SNAP tests were positive & an IFA was negative because the virus had not progressed to the bone marrow. I also wonder if the SNAP tests that were positive were done on the new 3way tests. Our shelter stopped using them because they were not dependable. Kat Parker <korruptaki...@gmail.com> wrote: >*Very scary.. see below..* > >------Original Message------ >From: Ellen Fawl >To: rescuealliancew...@yahoogroups.com >Subject: Scary FELV test results! >Sent: Nov 22, 2011 11:16 PM > >I need to share this so it can get to the FELV Lists and whomever is >following this testing debacle. We took in 5 Persians last week. We had >them combo tested with the standard Snap test. All five tested >positive. We had blood work done on one cat and it came back negative. >We assumed the tests were done wrong so they redid them two days ago. >All four remaining cats tested positive AGAIN. >We had blood work taken on all four, sent it in, and all four came back >negative. > >This is really scary stuff. Cats are killed all the time because they >test positive. Had we heard about these cats being in a shelter & >testing positive it's not likely we could have taken them in. The vet >office in Santa Cruz is going to follow up with the company, but if >there is anyone else out there tracking this stuff, I want to get the >information to them. >Ellen > > >* > >Love and Katnip, > ~Kat~ =^,,^= > > > >**"I'm Kat Parker. I park cats."** >**"Keep your kitties INSIDE, 24/7, 'cause an inside cat is a SAFE & >HAPPY >cat!"* > >_______________________________________________ >Felvtalk mailing list >Felvtalk@felineleukemia.org >http://felineleukemia.org/mailman/listinfo/felvtalk_felineleukemia.org _______________________________________________ Felvtalk mailing list Felvtalk@felineleukemia.org http://felineleukemia.org/mailman/listinfo/felvtalk_felineleukemia.org _______________________________________________ Felvtalk mailing list Felvtalk@felineleukemia.org http://felineleukemia.org/mailman/listinfo/felvtalk_felineleukemia.org _______________________________________________ Felvtalk mailing list Felvtalk@felineleukemia.org http://felineleukemia.org/mailman/listinfo/felvtalk_felineleukemia.org
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