i think that the rate of false negatives is really low, if there is one, because of the nature of the test--but i'm NOT a biologist/scientist, so maybe someone else can answer this one....
On 3/11/07, Debbie <[EMAIL PROTECTED]> wrote:
Is there such a thing as a false negative? -----Original Message----- *From:* [EMAIL PROTECTED] [mailto: [EMAIL PROTECTED] *On Behalf Of *TenHouseCats *Sent:* Sunday, March 11, 2007 5:09 PM *To:* FeLVTalk *Subject:* some tidbits on testing.... was in a friendly argument today about whether a cat who tests positive on the snap should be IMMEDIATELY retested with the IFA, or if one should wait and retest in 90-120 days. my theory is that, since a cat who is newly exposed might well test positive on both tests and still throw the virus off, and needs to be retested anyway, why spend the money...... her position was that the snap tests are so unreliable that an ifa might be negative while the snap is positive.... here's some stuff she pulled out of her files--she will check with her expert later this week (but she's been bugging her enough already this week) and i'll get attribution then, but i think this is pretty clear: "Virus isolation detects infectious virus (DNA) in the plasma while immunofluorescence (ie IFA or Hardy Test). demonstrates viral antigen (proteins) in the white blood cells. Either of these methods is generally regarded as the definitive (gold standard) test for FeLV and there is very good agreement between the results of the two. PCR is not widely available. This test detects FeLV-specific DNA in the white blood cells. A problem is that although it identifies viraemic cats, PCR also detects residual DNA in some cats that have recovered from FeLV infection and will continue to be completely healthy. Before PCR can be used routinely for FeLV diagnosis, further research is required to clarify how the results should be interpreted." sounds to be to be almost exactly the situation with FIV when they first started trying to identify the naturally occurring strain from the vaccine-induced one--yep, it can be done, and yep, it'll be a great test once perfected. but so far, it hasn't been standardized in terms of what the results even MEAN.... -- Spay & Neuter Your Neighbors! Maybe That'll Make The Difference.... MaryChristine AIM / YAHOO: TenHouseCats MSN: [EMAIL PROTECTED] ICQ: 289856892 -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.446 / Virus Database: 268.18.8/718 - Release Date: 3/11/2007 9:27 AM -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.446 / Virus Database: 268.18.8/718 - Release Date: 3/11/2007 9:27 AM
-- Spay & Neuter Your Neighbors! Maybe That'll Make The Difference.... MaryChristine AIM / YAHOO: TenHouseCats MSN: [EMAIL PROTECTED] ICQ: 289856892
