Indirect biomarkers of blood doping: A systematic review

Liquid vs dried blood matrices: Application to longitudinal monitoring of androstenedione, testosterone, and IGF-1 by LC-MS-based techniques

BACKGROUND

Dried blood spots have recently been approved by the World Anti-Doping Agency as an alternative biological matrix for testing of doping substances. However, their use is limited to the detection of non-threshold compounds without a Minimum Reporting Level due to the numerous issues related to quantitative analyses and the limitation on testing capabilities of a haemolysed matrix.

AIM

In this study androstenedione, testosterone and IGF-1 were longitudinally monitored in four different blood matrices to evaluate the potential of liquid capillary blood as an alternative matrix for quantitative determination in doping control analysis.

METHODOLOGY

The analytical protocols developed to pretreat 20 μL of the blood matrices selected were based: i) for testosterone and androstenedione, on supported liquid extraction for liquid blood matrices, and on ultrasonication in the presence of methanol for dried blood matrices; ii) for IGF-1, proteins precipitation followed by evaporation of the supernatant was used to pretreat both liquid and dried blood matrices. The detection for all the target analytes was performed using liquid chromatography coupled to mass spectrometry. The analytical workflows, once optimized, were fully validated according to the requirements of World Anti-Doping Agency and ISO 17025 standard and used for the analysis of venous (serum) and capillary (liquid plasma and dried whole blood collected using either volumetric or non-volumetric devices) blood samples collected from 7 healthy subjects.

RESULTS

The validation results showed satisfactory performance as related to specificity, sensitivity, matrix effects, linearity, accuracy, and precision in all the blood matrices evaluated despite the limited volume of sample used. The analysis of the different blood matrices collected from the subjects showed non-significant differences between the levels of testosterone and androstenedione measured in dried (fixed volume collected) and liquid matrices. An acceptable underestimation (lower than 15 %) was observed in capillary plasma compared to venous serum. The testosterone/androstenedione ratio was similar in all the blood matrices considered (bias lower than 5 %), indicating this parameter was not affected by either the blood matrix or collection device selected. For IGF-1, the levels measured in liquid blood matrices differed significantly (bias higher than 20 %) from those measured in dried whole blood matrices, suggesting haemolyzed blood might represent a challenge for the determination of macromolecules, mainly due to the complexity of the whole blood matrix in comparison to plasma/serum.

NOVELTY

The outcomes of our study suggest that liquid capillary blood might open new avenues to blood microsampling in doping control field. It represents an efficient alternative to overcome the issues related to venous blood and dried blood spot sampling. Furthermore, it also allows greater frequency of blood sampling, with minor discomfort and without needing a phlebotomist, for analyses that can only be performed in blood samples, with an increased probability to detect and report Adverse Analytical Finding.

Establishing Personalized Blood Protein Reference Ranges Using Noninvasive Microsampling and Targeted Proteomics: Implications for Antidoping Strategies

To prevent doping practices in sports, the World Anti-Doping Agency implemented the Athlete Biological Passport (ABP) program, monitoring biological variables over time to indirectly reveal the effects of doping rather than detect the doping substance or the method itself. In the context of this program, a highly multiplexed mass spectrometry-based proteomics assay for 319 peptides corresponding to 250 proteins was developed, including proteins associated with blood-doping practices. "Baseline" expression profiles of these potential biomarkers in capillary blood (dried blood spots (DBS)) were established using multiple reaction monitoring (MRM). Combining DBS microsampling with highly multiplexed MRM assays is the best-suited technology to enhance the effectiveness of the ABP program, as it represents a cost-effective and robust alternative analytical method with high specificity and selectivity of targets in the attomole range. DBS data were collected from 10 healthy athlete volunteers over a period of 140 days (28 time points per participant). These comprehensive findings provide a personalized targeted blood proteome "fingerprint" showcasing that the targeted proteome is unique to an individual and likely comparable to a DNA fingerprint. The results can serve as a baseline for future studies investigating doping-related perturbations.

Recent advances in mass spectrometry for the detection of doping

INTRODUCTION

The analysis of doping control samples is preferably performed by mass spectrometry, because obtained results meet the highest analytical standards and ensure an impressive degree of reliability. The advancement in mass spectrometry and all its associated technologies thus allow for continuous improvements in doping control analysis.

AREAS COVERED

Modern mass spectrometric systems have reached a status of increased sensitivity, robustness, and specificity within the last decade. The improved sensitivity in particular has, on the other hand, also led to the detection of drug residues that were attributable to scenarios where the prohibited substances were not administered consciously but rather by the unconscious ingestion of or exposure to contaminated products. These scenarios and their doubtless clarification represent a great challenge. Here, too, modern MS systems and their applications can provide good insights in the interpretation of dose-related metabolism of prohibited substances. In addition to the development of new instruments itself, software-assisted analysis of the sometimes highly complex data is playing an increasingly important role and facilitating the work of doping control laboratories.

EXPERT OPINION

The sensitive analysis and evaluation of a higher number of samples in a shorter time is made possible by the ongoing developments in mass spectrometry.

Annual banned-substance review 16th edition-Analytical approaches in human sports drug testing 2022/2023

In this 16th edition of the annual banned-substance review on analytical approaches in human sports drug testing, literature on recent developments in this particular section of global anti-doping efforts that was published between October 2022 and September 2023 is summarized and discussed. Most recent additions to the continuously growing portfolio of doping control analytical approaches and investigations into analytical challenges in the context of adverse analytical findings are presented, taking into account existing as well as emerging challenges in anti-doping, with specific focus on substances and methods of doping recognized in the World Anti-Doping Agency's 2023 Prohibited List. As in previous years, focus is put particularly on new or enhanced analytical options in human doping controls, appreciating the exigence and core mission of anti-doping and, equally, the conflict arising from the opposingly trending extent of the athlete's exposome and the sensitivity of instruments nowadays commonly available in anti-doping laboratories.