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Discussion Starter · #1 ·
CL tests aren't the most accurate out there. This goat has never had a visible abscess and is about 2.5 years old. None of my goats have ever had a visible abscess. I tested for disease myself this year, and this is what I got for one goat. Can someone please remind me what marginal results can mean?

"Optical Density (OD) results for serum samples that are equal to or greater than 0.658 are considered positive. Results between 0.358 and 0.658 are considered marginal." "OD 0.422"
 

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I'm getting to where I really don't like the CL tests very much because of exactly what you just stated. The CL test is one of the least reliable, with 15-20% of them reporting a false positive according to a lab researcher I spoke to earlier this year when trying to interpret my own herd's results. False negatives are also not uncommon. Giving CD+T vaccinations prior to testing can result in false positives, as can having a goat that is experiencing stress or illness. Low positives and marginal results should be suspect. I had a doe test low positive last year that tested marginal this year. If she actually had a CL infection then the titers should never, under any circumstance, go down. And hers did. So these days I'm looking at the CL test a lot more suspiciously then I did in the past. None of my goats have ever exhibited any abscesses.
 

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The ELISA B test is the most accurate with a 1 in 50 chance for a false-positive and a 3 in 50 chance for a false-negative, so it depends on which ELISA test the lab was using. False positives and negatives happen, so don’t worry yet.

Always retest. Marginal can be false, can indicate exposure or active infection, or even be evidence that they’ve been CL vaccinated before.

Have you purchased this goat or was it born on your farm?
 

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Discussion Starter · #4 ·
Wow, @Damfino I didn't know the false positive rate was that high. I was expecting 5% or lower.

@CountyLineAcres The lab did not specify what test they use. The report is pitifully low on info, actually. This goat, Ruby, was born on my property and was purposefully not vaccinated for CL, so that I could test for disease and have it come back negative unless a goat was sick with it.

All of my goats have theoretically come from clean, tested herds, but way back when I bought Ruby's mom, I did not know to ask to see the test results and just took the breeder's word for it.
 

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Discussion Starter · #6 ·
I'll have to see how feasible it is to use a different lab. The vet did the blood draw for me, and they only send things to one lab. They aren't terribly flexible. I currently can't do blood draws on my own for health reasons.
 

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Discussion Starter · #8 ·
Thanks!
 
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