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Minimum Required Performance Level (MRPL).

Feb 12, 2010
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Confusion,

Since there is no Limit of Detection for Clenbuterol, instead a adverse analytical finding (which happens to be treated as positive test).

WADA Accredited Labs must be able to detect Clenbuterol at a level of 2ng/ml and then this is Minimum Required Performance Level (MRPL)

Highest Clenbuterol Level in Contador's blood (July 21) is 50pg/ml.

Not a genius here but Nanograms are higher then Picograms.

How can a Lab or whomever justify Quantifying Positives for something they can't even measure in concentrations that low?

What is the repeatability for that measurement?
Does the Lab run "Known Standards" that show they can detect that low?
Do they have to spike the sample so they can even detect Clenbuterol at those levels?

I realize these are high level Labs here, but this seems a little wacky.
 
Wolves-Lower said:
Confusion,

Since there is no Limit of Detection for Clenbuterol, instead a adverse analytical finding (which happens to be treated as positive test).

WADA Accredited Labs must be able to detect Clenbuterol at a level of 2ng/ml and then this is Minimum Required Performance Level (MRPL)

Highest Clenbuterol Level in Contador's blood (July 21) is 50pg/ml.

Not a genius here but Nanograms are higher then Picograms.

How can a Lab or whomever justify Quantifying Positives for something they can't even measure in concentrations that low?

What is the repeatability for that measurement?
Does the Lab run "Known Standards" that show they can detect that low?
Do they have to spike the sample so they can even detect Clenbuterol at those levels?

I realize these are high level Labs here, but this seems a little wacky.

If you want to get a contract from WADA for Clenbuterol testing you have to be able to test down to 2ng/ml as a minimum. It's a minimum performance standard, not a limit. If you can test to lower concentrations even better. That's what happened here. The Koln lab can test down to minute concentrations of Clen and they got the job of testing Alberto.

If an even more advanced lab can find one molecule of Clen in an athlete's body it will be the same problem because there is a zero threshold for Clen.
 
May 20, 2010
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Polyarmour said:
If an even more advanced lab can find one molecule of Clen in an athlete's body it will be the same problem because there is a zero threshold for Clen.

Many seem to want to point to the small amount of clen detected in AC's sample. That is not the issue. The rules clearly have a zero tolerance for this substance and every UCI cyclist is held to this standard.

AC and his handlers are trying to argue the small amount detected supports his claim that it came from contaminated meat. His fans claim it is a witch hunt since the amount detected could not have possibly enhanced his performance at the Tdf. These arguments are specious at best since there are a number of plausible explanations indicative of illegal doping as has been discussed throughout the clinic.

Bottom line with clen is zero tolerance. As often as other cyclists are tested, if contaminated meat were the likely source, this would not be the first occurrence.
 
It's probably important to note that most of the tests for clenbuterol are 'qualitative', not 'quantitative'.

That means, they don't reliably produce a number of the amount present. In Contador and the RS riders cases, the number quoted are not known to be accurate, but have hugh potential variance.

The tests are designed to determine if there is any there, not how much. "Not that much" is still present, for these purposes.

This is why a threshold for this type of test isn't particulary relevant. Talking about quantities in this case is, in fact, a red-herring.

If you are asking the wrong questions, it doesn't matter what the answer is.

-dB
 
Feb 12, 2010
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I guess I am a little at a loss.
Irrespective of how the Clenbuterol came into his body, I find it bad analytical chemistry to have a MRPL but not LLOD (threshold level).

Was a baseline study done to proves there is no need for a LLOD? In other words you cannot have "any level is an adverse level" without unequivocal proof that the only way Clenbuterol can get into body is through deliberate ingestion and not present in whole population through factors outside their control.