It was a positive drug test from a urine sample collected in 2005, but not re-tested until 2013, that set in motion the stripping of third place from Andrei Mikhnevich of Belarus and the upgrading of Armstrong from fourth to bronze at the 2008 Summer Games.
The International Association of Athletics Federations (IAAF), which is the world governing body of track and field, now stockpiles samples in frozen storage for re-testing as analysis techniques become more sophisticated at detection.
Former Canadian Olympian Abby Hoffman serves on the IAAF's anti-doping doping and medical commission. She understands why people might ask, "what took so long?"
"Some people might think 'what the heck was wrong with the IAAF? Were you guys sleeping from 2005 to 2013? Why didn't you get these samples out earlier?,'" Hoffman said.
"There were good reasons why these samples from 2005 were only re-tested in 2013."
In re-analyzing urine samples from the 2005 world track and field championships, the IAAF was running up against an eight-year statute of limitations on re-testing. The organization waited as long as possible in order to have the most advanced drug-testing technology.
And there was only going to be one more chance at catching cheaters, because the stored samples yield just enough urine for one more test.
"There was no point in getting them out earlier," Hoffman explained. "You don't do re-testing until you're pretty sure that the methodology you have is a sufficient advance, that is if there's anything you didn't pick up the first time, you've got a reasonable shot of picking it up this time.
"You only have enough urine left to do one more test, so you don't waste that opportunity," she continued. "When you ask an athlete to give a sample at the outset, you can't be asking them to supply a half a gallon of urine."
Mikhnevich won a world title in 2003 after serving a two-year suspension for doping. So what was a second doping offence resulted in a lifetime ban and the stripping of all his results post-2005.
Mikhnevich was busted the second time for a combination of the stimulant clenbuterol and the steroids methandienone and oxandrolone, which aren't new performance enhancers.
"One of the things that is kind of surprising for some of us is some of the substances that athletes get caught with are kind of the same old substances," Hoffman observed. "Ben Johnson got caught for stanozolol. There are still people using stanozolol today.
"When we're talking about new analytical methods, it could be to detect a new doping product, but it's often to detect minute quantities that would not have been picked up years earlier in tests that wouldn't have the same level of sensitivity."
The statute of limitations on re-testing has been extended as of this year from eight to 10 years.
Retaining and re-testing samples is expensive and isn't without controversy. Hoffman considers it a powerful deterrent to dopers who might beat science on the day of competition, but can't be sure they'll beat the science of the future.
"If you're an athlete, not only do you need to be worried about what your result is going to be on the date you're tested, you need to be worried about 10 years of further scientific evolution that might allow something not detected in 2014 to be detected in 2024," she said.
"The success rate, for lack of a better term in re-testing, is very high. By that I mean the number of positive test results that come to light in this re-testing, it's really high compared to testing at an Olympic Games or world championships."