An analytical method known as gas chromatography combustion isotope ratio mass spectrometry (GC/C/IRMS) has emerged as one of the most potent weapons in the anti-doping police's armoury, in new testing statistics published by the World Anti-Doping Agency (WADA).
WADA's 2018 Testing Figures Report – a 343-page compendium of data relating to the 340,000-plus samples analysed in WADA-accredited laboratories during the year – shows that GC/C/IRMS yielded a 3.52 per cent adverse analytical finding (AAF)-rate in 2018.
This compares with an overall AAF figure of just 1.42 per cent.
Anti-doping authorities are often criticised for spending large sums on tests which produce a far lower proportion of positives than the percentage of athletes suspected of using performance-enhancing drugs.
In spite of the method's apparent effectiveness, the number of GC/C/IRMS tests conducted was said to be down marginally at 5,231 in 2018.
WADA explains that GC/C/IRMS is "connected to the steroidal module of the [Athlete Biological Passport]".
It can be triggered, the agency says, "by the athlete biological passport or requested by the [testing authority] based on other information".
In Summer Olympic sports, the data indicates that just over 3,500 GC/C/IRMS urine tests were conducted for steroid profile markers, producing 119 AAFs.
More than 40 per cent of these AAFs – 51 in total – came in weightlifting, a sport whose doping problem is well-known.
This was even though weightlifting accounted for less than 12 per cent of GC/C/IRMS tests conducted in the Summer Olympic sport sphere.
Cycling accounted for 23 of the remaining AAFs and athletics 12.
The test was also highly effective in securing AAFs for other targets such as 19-norandrosterone and boldenone.
Of 72 samples tested this way for the first of these substances, 21 produced AAFs, including all five in wrestling, two out of four in rugby union and six out of 23 in athletics.
With boldenone, there were 19 AAFs from 44 samples; this included five out of five in cycling and five out of nine in weightlifting.
Curiously, for Winter Olympic sports, the WADA data indicates that just over 400 samples tested via the GC/C/IRMS method resulted in not a single AAF.
Of the more than 4,000 occasions across all sports when substances were identified as AAFs in 2018, 44 per cent involved anabolic agents, 15 per cent stimulants and 14 per cent diuretics and other masking agents.
Of anabolic agents, 17.5 per cent of occurrences were clenbuterol and nearly 13 per cent stanozolol.
Cocaine was third on the stimulant list, just behind amphetamines and methylphenidate.
More than half of AAFs in the category labelled peptide hormones, growth factors and related substances involved erythropoietin (EPO), while only two out of 115 cases were for growth hormone.
Almost a third of AAFs in the hormone and metabolic modulators category were for meldonium.
The 2018 Testing Figures Report can be read here.