A vs. B sample, drug testing

On Thu, 25 Aug 2005 23:24:53 GMT, "Monty" <[email hidden]>

Quoted message said:

What is the difference between A and B samples when drug testing?

Monty

One has a big A on it and the other has a big B on it. ;-)

The only difference is that the A is tested first. The B is used if
there is a positive finding in the A sample. Other than that they
should be EXACTLY the same.

"Monty" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

What is the difference between A and B samples when drug testing?

Right after the rider gives the sample it is split into two samples so that
one can be tested and the other held in case the first proves positive.
There's always the chance that there can be contamination of a sample and in
fact this isn't all that rare. In one lab I know of. the scientist was
eating his lunch off of the same counter he used to test blood for HIV!
Luckily he only caught hepetitis but that nearly killed him. It took him two
years to recover fully.

That's why a "B" Sample can't be split and then assumed to be an "A" and a
"B" sample. At any point AFTER the initial sample contamination could be
encountered. This isn't a case of a "bad" test but a matter of being able to
know that the sample is unlikely to encounter the same source of
contamination.

In article <[email hidden]>, [email hidden]
says...

Quoted message said:

What is the difference between A and B samples when drug testing?

Same pee, different vials.
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Alex