Reticulocytes Level of Iron Gas chromatography-combustion-IRMS The gas chromatography-combustion-IRMS is a way to detect any variations in the isotopic composition of an organic compound from the standard. This test is used to detect whether or not synthetic testosterone was consumed, leading to an increased abnormal testosterone/epitestosterone (T/E) level. Assumptions: 98.9% of the carbon atoms in nature are 12C the remaining 1.1% are 13C The lower the13C to12C ratio, the more likely that synthetic testosterone was used. Athlete biological passport The athlete biological passport is a program that tracks the location of an athlete to combat doping in sports. This means that the athlete can be monitored and drug tested wherever they are and this data can be compared to the history of their doping test results. There is an ongoing discussion about how this measure can be seen as a violation of an individual's privacy. Re-testing of samples According to Article 6.5 in the World Anti-Doping Code samples may be re-tested later. Samples from high-profile events, such as the Olympic Games, are now re-tested up to eight years later to take advantage of new techniques for detecting banned substances. Cheating the tests Athletes seeking to avoid testing positive use various methods. The most common methods include: Urine replacement, which involves replacing dirty urine with clean urine from someone who is not taking banned substances. Urine replacement can be done by catheterization or with a prosthetic penis such as The Original Whizzinator. Diuretics, used to cleanse the system before having to provide a sample (which have also been placed in lists of banned substances themselves to circumvent this practice). Blood transfusions, which increase the blood's oxygen carrying capacity, in turn increasing endurance without the presence of drugs that could trigger a positive test result. To avoid being tested during training periods, athletes can make themselves unavailable. To mitigate this, athletes have to report their location at any time. If intended doping tests could not be done because the athlete could not be found, three times during a year, it's considered a doping violation, same as refusing a test. There is a web site and a phone app, called ADAMS, in which athletes are expected to report their location.ADAMS Mobile App Validity Donald Berry, writing in the journal Nature, has called attention to potential problems with the validity of ways in which many of the standardised tests are performed;[subscription required] in his