For those looking for a peer-reviewed source with multiple references:
http://www.thinkmuscle.com/ARTICLES/...drug-tests.htm
the most relevent section:
[ QUOTE ]
Thus, since NA and NE are endogenous steroids, it's not the presence of nandrolone metabolites that constitutes a positive drug test for nandrolone. As such, we need to be able to distinguish the natural endogenous products from the exogenous ones, including the anabolic steroid nandrolone and the various prohormones such as norandrostenedione and norandrostenediol.
To this end, the IOC and other sporting federations have decided to establish a urinary threshold concentration above which constitutes a positive doping test for the anabolic steroid nandrolone and/or one or more of the prohormones. And this is where the major problem lies.
Unfortunately for the athletes, establishing a urinary threshold level for nandrolone metabolites is currently a difficult and speculative process, due largely to the lack of scientific knowledge within this area.
For example, endogenous production has been shown in several studies to vary and has been found to be as high as 37 ng per ml in male subjects. (Debruyckere et al., 1990) No specific studies have been undertaken to determine excretion rates in females, although it has been demonstrated that natural female urinary NA concentrations are significantly higher than males (Ciardi et al. 1999).
Use of a threshold level also becomes difficult when environmental and physiological stress results in changes in the excretion rate of steroidal metabolites. Recent work by Le Bizec et al. (1999) has demonstrated that exercise can result in significant increases in nandrolone metabolite concentrations in voided urine. It was found that NA abundance within a soccer players urine increased by 300% during the course of a game.
As well, preliminary data from a study in the UK has shown that urinaly levels of NA may vary secondary to exercise, the use of non-banned nutritional supplements, and perhaps even from sickness, another form of stress for the body. (see Appendix 1 below)
Unfortunately, due to the lack of scientific knowledge in this area, it is not possible to conclusively state the natural range of nandrolone metabolite excretion in males or females, under both natural and stress conditions, with or without the use of various non-banned nutritional supplements. As a result, it is also impossible to set a scientifically or legally sustainable threshold level above which a doping offence can be proved to have been committed.
[/ QUOTE ]
Host of references at the end of the article.
Based on Sherk's seemingly abnormal physical stature and his observed insane workout regimen and barage of legal supplements (ignoring for the moment any potential illegal supplements) based on the referenced work above (assuming a lack of negative peer reviews, which I freely admit I have not taken the time to research) it certainly seems reasonable to suspect that the natural level in Sherk's body given the above could have resulted in the level tested.
Not saying he is, not saying he isn't.
Personally if I were in charge and I wanted to get serious and heavily regulate it, I would have the fighters under contract subjected to monthly (maybe bi-monthly) blood tests. Any state which wants to fight under the unified rules sets up at least one sanctioned test facility in the sanctioned state -- hell, if I'm Zuffa LLC I do it at my own expense if necessary, its not like I'm not running at a decent profit margin. I move exclusively to blood testing via gas chromatography / mass spectrophotometry with multiple samples. I completely revamp the rules, the testing, and the penalties (I'd set it at one year no-contact suspension + 100% of fight purse + bonus money).
Then when I had this infrastructure and proved it work, I'd then lobby the NFL, MLB, and NBA to adopt the same policy using my facilities (or even lobby the national legislature to enforce it, wouldn't be infeasible) thus step 3 = Profit.
-P