Have you noticed a continuing thread in the drugs-in-sport-issue is the testing procedures themselves? Is it scientifically valid? Has it been independently validated? Is it reliable? How much of a substance can be found, is it a reasonable measurement? And then what to do with that information the regulatory side. Is it a threshold substance? And what the hell does that mean anyway? Threshold substance is defined as:
Any material (e.g., glucose) that is excreted in the urine only when its plasma concentration exceeds a certain value, termed its threshold.
Following that determination, should there be a baseline limit amount for that particular substance? Alternatively, is a certain amount considered tolerable, or at least within normal parameters? All these questions, and many more, apparently remain unanswered definitively. Of course, there is certainly a wide gulf between what are the reasonable inquires into the process and the red herrings trotted out to the press by the legions of accused as damage control of the accused athlete’s public image.
From what I understand at the present moment in time (which, arguably, isn’t much), clenbuterol is not a threshold substance. As such, there is no baseline acceptable limit. If it shows up in a urine analysis, guilt has been established.
The new wrinkle is the alleged presence of plasticizers in Alberto Contador’s blood sample from July 21st. If you’re asking what in the hell a “plasticizer” is, you are not alone. I had no idea. I’ll bet google knows. Very detailed (perhaps too detailed) write ups can be found at the following links:
In case you’re wondering, as I was, disposable blood bags are made of pvc. (See tradekey.com/ks-disposable-pvc-blood-bag.)
French sports paper L’Équipe has reported that tests undertaken on Alberto Contador’s urine sample from the Tour de France have revealed the presence of a plastic component that is found in blood transfusion bags. According to the paper, this could indicate that the three-time Tour winner underwent a blood transfusion before being undergoing a drug control on July 21 that revealed the presence of Clenbuterol.
The paper says that investigators working on Contador’s case at the laboratory in Cologne have tested the Spaniard’s urine using a method developed by Dr Jordi Segura at a laboratory in Barcelona. The method enables the detection of a plastic substance that derives from bags used to transport blood.
According to L’Équipe, this substance, known as di(2-ethylhexyl), has been found in Contador’s urine. This suggests that Contador could have received a transfusion of blood that he gave earlier in the season and which contained traces of Clenbuterol.
More on the subject over at velonation.com/…Alberto-Contador-insists-hes-had-no-transfusions.
The crux of the matter is twofold. Firstly, this test has not been validated.
L’Équipe adds that Segura’s method, details of which were published in 2009, has not yet been validated by the anti-doping authorities and will require further testing before it can be ratified.
Secondly, these pesky plasticers can find their way into the blood sample after the sample was drawn.
Frankly, what I know about this would fit on one side of a three by five card, written in purple crayon. I did find a few studies and their summations online. And, I want to be clear on this point, I have no idea if what I’m blockquoting below is representative of the current state of affairs in scientific thought on the subject. It only begs more questions and further inquiry.
In view of the many possible sources of there plasticers in the hospital and laboratory environment, we deemed it advisable to study in more detail blood samples from normal individuals, taking special care to prevent the introduction of such compounds from outside sources during sample workup.
From the conclusion of the article:
Several laboratory sources of contamination were finally identified. In one case, filter papers used to facilitate phase separation between chloroform and water were found to contain phthalate esters at rather high levels. In another case, phthalate esters were found in bulk quantities of alcohol used in early chloroform-ethanol extractions. In a third case, di-2-ethylhexyl adipate was observed to be present in the plastic wrappings at the top of solvent bottles.
While there seems to be no doubt whatsoever that plasticers are to be found in blood samples where the blood has been stored or in contact with plastic apparatus, such as blood bags, etc, we conclude on the basis of our experiments that indications of plasticizer in humans under normal conditions should be viewed with a great degree of caution.
Also, pvc products are used in a legal fashion in professional cycling. Does the use of a saline drip also introduce plasticers into the bloodstream? I think Art nailed it in the comment section earlier today:
I’m curious how they can differentiate between blood bag residuals and saline IV bag residuals. IV fluid replacement during stage races is common and legal. I would have guessed the bags were the same material.
Are plasticers to be a threshold substance? Should they be? Is it reasonable that they could be introduced into a blood sample via the legal and tolerated use of IV drips, or post-sample through manner of storage?by