Quote:
Originally Posted by Ray
All immunoassay tests have false positives and false negatives, don’t they?
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If the test strip is working (good test line), there can be false negatives for the two viruses that can by tested for if the hunk of leaf chosen has a low titer... a very fresh leaf can do that. I tend to go for more mature leaves, to improve my odds of finding something if it is there. If the line is very faint, it's a "maybe positive and maybe not" ... worth retesting after some time, taking a sample from a different leaf. Of course, there are other viruses that we just don't have tests for. A few can be done in the lab, but there certainly are some that we don't have tests for. If a plant is doing badly and tests negative, it's still a candidate for the garbage can.