United States Anti-Doping Agency

The steroidal module of the Athlete Biological Passport (ABP) longitudinally monitors five ratios between urinary concentrations of endogenous anabolic and androgenic steroids. Even though it has improved detection of testosterone doping, the interpretation of data from multiple discrete biomarkers is complex. This study sought to create a single score to identify doping rather than relying on the interpretation of each parameter alone. A Bayesian model was used to define an ABP sequence probability for each biomarker to assess the extremity of a measurement relative to the expected levels from ABP. This was used to discriminate between doped and presumed clean individuals based upon pattern classification of biomarkers using classification algorithms. Data were obtained from laboratory-controlled experimental studies as well as routine doping control tests. A laboratory model (where classifier is trained using the laboratory-controlled data only) and a mixed model (where classifier is trained on combined laboratory-controlled and doping control data) were developed and tested on the doping control data. Logistical regression was seen to have the best classification performance across the methods used, with the Abnormal Steroid Profile Score (ASPS) representing the estimated probability from the logistical regression model. Classifier performance produced an AUC of 0.67 and 0.75 when trained on the laboratory model and the mixed model, respectively, with T/E and 5α-Diol/5β-Diol representing the main biomarkers driving the ASPS. These findings demonstrate that the ASPS can discriminate between the doping status of individuals, even if a mixture of steroids, administration methods and doses are used.

The opinions and assertions expressed herein are those of the authors and do not reflect the official policy or position of the Uniformed Services University or the Department of Defense. The mention of trade names, commercial products, or organizations does not imply endorsement by the Department of Defense, nor the U.S. Government. The authors have no relevant financial interests, activities, relationships, and/or affiliations to disclose. The data that support the findings of this perspective are personal observations or publications available in PubMed.

This study provides data on the prevalence of animal growth promoter residues through a comprehensive US surveillance approach targeting multiple species via retail purchases. Over a year, residue levels were analyzed in beef, pork, and poultry samples from eight US cities, screening for a panel of anabolic steroids, other anabolic agents, selective androgen receptor modulators (SARMs), and non-prohibited controls using sensitive high-resolution tandem mass spectrometry. Thirteen of the 53 beef samples tested positive for ractopamine, with a peak concentration of 14 ng/g in liver-well below CODEX and FDA maximum residue limits (MRLs). Trenbolone-17β and estradiol were also found in beef but remained within MRLs, indicating no health risk. In addition, pork samples showed minimal contamination, with just one pork kidney testing positive for nandrolone (0.08 ng/g) under the limit of detection and estradiol (0.5 ng/g), likely from endogenous hormone production in intact male pigs. Pork muscle and liver samples were residue-free. Chicken samples showed limited residues, with estradiol detected in three out of 35 muscle samples at 0.01 ng/g. These findings highlight the effectiveness of regulatory practices in limiting growth promoter residues in commercial meat, affirming that residue levels in meat products remain within regulatory limits and reinforces consumer safety and confidence.

This study evaluated the implementation of a novel Case-Based Team Learning session on drugs in sports for preclinical first-year (MS1) and second-year (MS2) medical students. The session aimed to introduce fundamental concepts of performance-enhancing drugs, anti-doping regulations, and patient communication strategies within the context of sports medicine. Post instructional survey data on the learning environment and qualitative feedback responses were collected from 177 MS1 and 166 MS2 students. Results of the quantitative data showed that MS1 students rated the session more positively than MS2 students. Qualitative data was collected through open-ended questions, allowing for more detailed and nuanced responses. AI models were used to identify common themes and patterns in the qualitative feedback responses. These responses provided valuable insights for future curriculum refinement and development of the newly implemented drugs in sports education program. Both cohorts appreciated the interactive nature of the session and real-life applications but identified areas for improvement, including better alignment with curriculum objectives and exam preparation. Key challenges included balancing content relevance with broader medical education goals and integrating communication skills training within a large group setting. Faculty reflection highlighted the need for restructuring the session to better match instructional block content and USMLE Step 1 exam preparation. Future iterations will focus on emphasizing drug pharmacology, mechanisms of action, and physiological effects for MS1 students, while providing opportunities for more comprehensive knowledge integration through the case studies for MS2 students. This evaluation of the learning session underscores the importance of iterative curriculum development in medical education, particularly when introducing novel topics like drugs in sports. Samuel Pelobello was a Walter E Macpherson and Lifestyle Medicine Summer Research Fellow This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

Journal Article Breaking Boundaries: Exploring Performance Enhancement and Anti-Doping Testing in Sports Get access Imir G Metushi, Imir G Metushi Assistant Professor, Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States Address correspondence to this author at: Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California Los Angeles, 10833 Le Conte Ave., CHS A3-231S, Los Angeles, CA 90095-1732, United States. E-mail imetushi@mednet.ucla.edu. Search for other works by this author on: Oxford Academic Google Scholar Allison Wagner, Allison Wagner Director of Athlete and International Relations, OLY, Silver Medalist, Former World Record Holder, World Champion, NCAA Champion, United States Anti-Doping Agency, Colorado Springs, CO, United States Search for other works by this author on: Oxford Academic Google Scholar Brian Ahrens, Brian Ahrens Director of Olympic Analytical Laboratory, Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States Search for other works by this author on: Oxford Academic Google Scholar Magnus Ericsson, Magnus Ericsson Director of Laboratoire AntiDopage Francais, Universite Paris-Saclay, Orsay, France Search for other works by this author on: Oxford Academic Google Scholar Olivier Rabin, Olivier Rabin Professor, Senior Director of Science and Medicine, World Anti-Doping Agency, Montreal, QC, Canada Search for other works by this author on: Oxford Academic Google Scholar Tim Sobolevsky, Tim Sobolevsky Senior Scientist at Olympic Analytical Laboratory, Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States Search for other works by this author on: Oxford Academic Google Scholar Travis T Tygart Travis T Tygart Chief Executive Officer, United States Anti-Doping Agency, Colorado Springs, CO, United States Search for other works by this author on: Oxford Academic Google Scholar Clinical Chemistry, Volume 70, Issue 7, July 2024, Pages 897–904, https://doi.org/10.1093/clinchem/hvae074 Published: 05 July 2024 Article history Received: 08 April 2024 Accepted: 08 May 2024 Published: 05 July 2024

The popularity of regenerative medicine has recently increased, with many athletes turning to orthobiologic therapies that utilize complex milieus of biological substances, such as stem cells and natural growth factors, to heal sports injuries faster. Commonly derived from donor and non-donor harvested tissues, these include umbilical cord blood, amniotic fluid, placental allografts, connective and adipose tissue. Many of these products are not well characterized and their safety and efficacy has not been proven. Orthobiologics, generally are not prohibited in sport if no exogenous growth factors or other prohibited substances are added after harvesting or during the administration process, and as long as they only return normal functioning of the affected area and do not enhance it. Use of these treatments by professional athletes, presents an ethical dilemma for anti-doping governance due to the unproven efficacy, possible health risks and potential to contravene the Spirit of Sport. The US Anti-doping Agency (USADA) adopted an orthobiologics Declaration of Use (DOU) policy in 2020 for the Ultimate Fighting Championship (UFC). PURPOSE: Document the use of orthobiologics within the UFC in order to assist in evaluating such products and provide an anti-doping status to athletes. METHODS: DOU were submitted to USADA in advance of treatment, including: Date of procedure, Product, Injury, and Course of treatment and reviewed by USADA. RESULTS: Over 50 stem cell DOU were submitted in 1y including over 15 individual products. Treatment was requested primarily for joint injuries sustained during competition or arising from overuse. The most common orthobiologic was umbilical cord derived Wharton’s Jelly following or in conjunction with surgical intervention. Despite the high amounts of growth factors and cytokines present, all but one DOU was approved since growth factors were not added post-harvesting. No adverse analytical findings were associated with orthobiologic use. CONCLUSIONS: The use of orthobiologics has exploded in UFC athletes. USADA continues to monitor the evolving field through a DOU process. More detailed studies are needed to characterize these products, ensure that the constituents lack the potential for performance enhancement, evaluate treatment efficacy and monitor their safety.

The hematological module of the Athlete Biological Passport (ABP) represents an important tool in the pursuit to detect blood doping in athletes. Currently, collecting blood samples for ABP analysis can be cumbersome, invasive, and expensive, involving a venous blood draw performed by a trained phlebotomist followed by cold-chain monitored shipping to the analysis laboratory. Developing innovative methods to collect and transport ABP blood samples while adhering to strict preanalytical and analytical requirements has the potential to greatly increase testing frequency and, consequently, the effectiveness of the ABP program globally. The focus of this study was to compare venous blood collections with capillary blood collections to determine if capillary samples could be used for ABP analysis without sacrificing the analytical integrity required for antidoping testing procedures. In this study, capillary blood was collected using the Tasso+ EDTA device (Tasso, Inc.), a novel microvolumetric device that collects liquid, whole blood from skin capillaries on the upper arm. Excellent laboratory agreement was observed between venous and capillary blood samples for the three main ABP parameters: HGB, RET%, and OFF-Score. Additionally, the stability of capillary samples after storage at 4°C, similar to what would be required during transport, was acceptable for up to 72 h following collection. Finally, we generated individual ABP profiles using the adaptive model for 10 participants and observed excellent agreement between venous and capillary profiles. These results indicate capillary blood collection is a viable alternative to venous blood collections for ABP analysis.

The purpose of this narrative review was to summarize available data on testosterone levels in normal, healthy adult males and females, to provide a physiologic reference framework to evaluate testosterone levels reported in males and females with conditions that elevate androgens, such as disorders of sex development (DSD), and to determine the separation or overlap of testosterone levels between normal and affected males and females. A literature review was conducted for published papers, from peer reviewed journals, reporting testosterone levels in healthy males and females, males with 46XY DSD, and females with hyperandrogenism due to polycystic ovary syndrome (PCOS). Papers were selected that had adequate characterization of participants, and description of the methodology for measurement of serum testosterone and reporting of results. In the healthy, normal males and females, there was a clear bimodal distribution of testosterone levels, with the lower end of the male range being four- to fivefold higher than the upper end of the female range(males 8.8-30.9nmol/L, females 0.4-2.0nmol/L). Individuals with 46XY DSD, specifically those with 5-alpha reductase deficiency, type 2 and androgen insensitivity syndrome testosterone levels that were within normal male range. Females with PCOS or congenital adrenal hyperplasia were above the normal female range but still below the normal male range. Existing studies strongly support a bimodal distribution of serum testosterone levels in females compared to males. These data should be considered in the discussion of female competition eligibility in individuals with possible DSD or hyperandrogenism.

Can we catch every person violating anti-doping rules through just a random drug test given the current resources? No. The police cannot catch every impaired driver, so should they stop trying? Regulators cannot catch every incidence of insider trading on Wall Street, so should we cease regulation of the finance industry? And should we stop performing Internal Revenue Service audits because some people successfully cheat on their taxes? The fundamental problem with the question posed based on a Bayesian analysis of testing numbers is that it assumes that catching every cheater through random drug testing is the sole purpose of an antidoping program. It is not. But before focusing on the role of drug testing in an antidoping program, why are antidoping rules important? To live together and achieve societal goals, we agree to a set of rules to govern our work and play. We accept rules against impaired driving, for example, because of the potential harm to others. We accept rules that the basketball rim is 3.05 m high and the court is 28 by 15 m to have a level playing field. Violating the rules that the athlete agrees to abide by to have equitable competition has its own name: cheating. When an individual cheats, whether in sport, at work, or on their taxes, it defrauds or takes something away from others. It is ethically and morally wrong, no matter how the individual tries to rationalize it. Cheating by violating antidoping rules is not a victimless crime. Cyclist Scott Mercier was forced to make the choice to quit the sport he loved because he was unwilling to become a fraud and risk his health. Shotputter Adam Nelson recently received his gold medal 9 years after the 2004 Olympic contest because reanalysis of the samples with new technology revealed …

The first documented use of testosterone as a performanceenhancing substance in sport began in the 1950s. The success of Russian weightlifters during this era led Dr. John B. Zeigler to surreptitiously obtain information from their trainers that they were using testosterone. Later, Zeigler would use Dianabol to enhance the performance of weightlifters at the York Barbell Club beginning in 1958. Once Pandora’s Box was open, it was impossible to close. The growth and widespread use of anabolic steroids in many competitive sports eventually led the U.S. Congress to schedule testosterone and other anabolic agents under the Anabolic Steroids Control Act in 1990 (Public Law 101647). For many years, the medical community argued that there was no proof that testosterone enhanced athletic performance. Finally, in 1996, Bhasin and co-workers showed that supraphysiological doses of testosterone indeed produced performance benefits (1), something the athletes had known for four decades. The urinary testosterone to epitestosterone (T/E) ratio was the first test to be used for evaluation of abuse of a natural (or endogenous) substance such as testosterone to enhance performance in sport. The production of reliable quadrupole gas chromatograph/mass spectrometers in the mid-1970s allowed more widespread study of urinary steroid profiles. Donike and coworkers (2) observed an unusual distribution of testosterone concentrations in samples collected at the Moscow Olympics in 1980. In 1982, Donike proposed the use of the urinary T/E ratio based on the observation that epitestosterone was excreted in the urine in a relatively constant amount and as such constituted a way to compensate for the variability in testosterone concentration that occurred as a function of the diluteness of the urine (2). Because the primary metabolite of testosterone is testosterone glucuronide, the procedure developed by Donike used -glucuronidase in the preparation of the samples for analysis. In 1983, the International Olympic Committee accepted a T/E ratio of greater than 6:1 as evidence of testosterone doping, based on the 99th percentile of the log normal distribution of ratio values established by Donike and his co-workers. It was soon clear that the T/E ratio based on population reference ranges had limitations. For example, it had been noted in 1970 that genetic make-up could have a significant effect on urinary testosterone excretion, whereas epitestosterone excretion was unaffected (3). As population T/E ratio data accumulated in the anti-doping laboratories, it was clear that there were two distributions of urinary T/E ratios in both men and women, one with a maximum frequency at a T/E ratio of about 0.1 and a much larger population with a maximum frequency at a T/E ratio of about 1. Within the anti-doping community, the smaller population was referred to as low mode, and it was known that administration of testosterone to low-mode individuals did not result in a T/E ratio above the population threshold (4). Jakobsson and her colleagues (5) provided the mechanism for lowmode excretion in 2006 when they demonstrated that the UGT2B17 gene deletion was the cause of significant differences in testosterone glucuronide excretion between Korean and Swedish men. In their current paper in this issue, JakobssonSchulze et al. (6) report that when subjects deficient in the UGT2B17 gene (del/del) receive exogenous testosterone, their T/E ratio does not rise above the current population-based threshold of 4:1. One potential route of excretion of testosterone in UGT2B17 del/del genotypes is through other phase II metabolites such as testosterone sulfate. Borts and Bowers (7) directly measured the concentrations of testosterone and epitestosterone sulfate and glucuronide using HPLC/tandem mass spectrometry. Low-mode excretors did not produce larger than normal amounts of testosterone or epitestosterone sulfate. There was also no change in the relative production of sulfate conjugates. Because phase II metabolism does not explain the difference in testosterone handling in these individuals, it would be interesting to know what phase I metabolism products are increased in individuals with the UGT2B17 del/del polymorphism. This information may help develop a more sensitive test for testosterone