A fast screening method for the detection of CERA in dried blood spots

Dried blood spots for erythropoietin analysis: Detection of micro-doses, EPO c.577del variant and comparison with in-competition matching urine samples

The abuse of recombinant erythropoietin (rEPO) and other erythropoietin (EPO) receptor agonists (ERAs) in sports prompted the need for sensitive detection methods of these substances. Dried blood spot (DBS) samples offer an easy solution for simultaneous collection of blood and urine during a doping control, but sensitivity issues are often presented as a challenge for routine EPO analysis from DBS. Its potential use for detecting rEPO micro-doses and the EPO gene c.577del variant thus needed further demonstration. Here, capillary blood collected from the arm skin of 111 athletes with Tasso-M20 (17.5 μL/spot), collected during professional triathlon competitions, were analysed. Also, venous blood samples from healthy volunteers were used to prepare several spots of 20 μL on Mitra VAMS (from an rEPO micro-dose study) and Whatman filter paper (from an EPO gene variant study). Immunopurification of 2 spots with MAIIA EPO Purification Gel Kit and analysis with sodium N-lauroylsarcosinate polyacrylamide gel electrophoresis (SAR-PAGE)/Western blot resulted in sensitive detection of (1) micro-doses of rEPO from Mitra VAMS, (2) endogenous EPO from Tasso-M20 in all in-competition subjects, and (3) the EPO c.577del variant from Whatman filter paper. Additionally, in-competition endogenous EPO was detected in DBS even when matching urine samples had undetectable EPO. In conclusion, this work demonstrated that DBS can be a useful complementary matrix to urine samples for EPO detection.

Use of RNA biomarkers in the antidoping field

There is growing evidence that various RNA molecules can serve as biomarkers for clinical diagnoses. Over the last decade, the high specificities and sensitivities of RNA biomarkers have led to proposals that they could be used to detect prohibited substances and practices in sports. mRNAs and circulating miRNAs have the potential to improve the detection of doping and expand the performance of the Athlete Biological Passport. This review provides a summary of the use of RNA biomarkers to detect human and equine doping practices, including a discussion of the use of dried blood spots as a stable matrix that supports and improves the general process of RNA biomarker detection. The advantages of RNA biomarkers over protein biomarkers are also discussed.

Detection of doping substances in paired dried blood spots and urine samples collected during doping controls in Danish fitness centers

The use of dried blood spot (DBS) in anti-doping can be advantageous in terms of collection, transportation, and storage compared with the traditional anti-doping testing matrices urine and venous blood. There could, nonetheless, be disadvantages such as shorter detection windows for some substances compared with urine, but real-life comparison of the detectability of prohibited substances in DBS and urine is lacking. Herein, we present a liquid chromatography-high resolution mass spectrometry (LC-HRMS)-based screening method for simultaneous detection of 19 target analytes from the doping substance categories S1-S5 in a single spot. Ninety-eight urine and upper-arm DBS (Tasso-M20) sample pairs were collected from fitness centers customers notified for doping control by Anti Doping Denmark, and three sample pairs were collected from active steroid users undergoing clinical evaluation and treatment at a Danish hospital. The analytical findings were cross compared to evaluate the applicability of the developed DBS testing menu in terms of feasibility and analytical performance. To our knowledge, this is the first study to compare the detectability of prohibited substances in DBS and urine samples collected in a doping control setting. Twenty-seven of the urine samples and 23 DBS samples were positive, and we observed a very high concordance (95%) in the overall analytical results (i.e., positive or negative samples for both urine and DBS). Collectively, these results are very promising, and DBS seems suitable as a stand-alone matrix in doping control in fitness centers likely because of the high analyte concentration levels in these samples.

Evaluation of a single Eporatio® micro-dose in urine and dried blood spots

Recombinant human erythropoietin (rhEPO) has been abused as a performance enhancer in sports for several years, but with advancements in detection methods, even micro-doses can be detected in dried blood spot (DBS) samples. Here, we present the results from an Eporatio® (epoetin theta) micro-dose administration study to detect rhEPO in DBS samples. Five healthy male volunteers received a 15 IU/kg subcutaneous dose of Eporatio®. Urine and DBS samples (Mitra® VAMS and Capitainer® B50) were collected 1, 10, 24, 36, 48 and 72 h after drug administration. After 1 h, all urine samples were negative for rhEPO, whereas 40% of DBS samples were considered suspicious. All samples between 10 and 48 h were suspicious for the presence of Eporatio®, except one urine sample that was negative at 48 h. After 72 h, 40% of urine samples and 60% of DBS samples were suspicious and would have proceeded to a confirmation analysis. DBS is an efficient complementary matrix to urine for detection of rhEPO micro-doses.

Stability of inflammation markers in human blood collected using volumetric absorptive microsampling (VAMS) under typical laboratory storage temperatures

Dried blood spots (DBS) collected on filter paper such as Guthrie cards are stored for years at room temperature. The assumption is that once dried, the samples remain stable and quantifiable indefinitely since the metabolites these were initially designed to measure, are known for their extended stability. The concentration of other blood proteins such as cytokines, however, are known to vary with storage even in liquid samples stored at -80 °C for extended periods of time. We sought to determine if cytokines are stable for up to 5 months when stored as a dried blood sample using volumetric absorptive microsampling (VAMS) devices. To test this, blood was collected from 4 healthy participants, spiked with recombinant cytokines, and collected into 30 µL VAMS devices. These prepared VAMS devices were stored at room temperature, 4 °C, or -20 °C for up to 5 months and matching VAMS liquid extracts were stored at -80 °C for the same period of time. At each timepoint, the samples were extracted from the VAMS devices and the extracts were analysed by Luminex® for quantification of up to 31 cytokines. These methods were also tested in a remote clinical study over a period of up to 8 months. Cytokine analysis revealed that room temperature, the current standard for DBS and VAMS storage, performed the poorest out of all storage temperatures with significant losses in 13/21 analytes compared to 4 °C at 5 months. Storage at 4 °C or colder performed well for the majority of analytes tested, however out of those, the optimal storage temperature differed for each analyte. There were a small number of analytes that performed poorly regardless of storage conditions and for fractalkine, this was found to be caused by inefficient recovery during extraction. Cytokine concentrations from finger-prick samples were also found to be much more variable that those in venous blood samples. Our results highlight the need to understand the stability of analytes of interest before committing to longitudinal collection and storage of samples in VAMS devices. These data give confidence that storage at 4 °C or colder was beneficial for cytokine stability. Wherein 25/31 cytokines were quantifiably stable at -20 °C when stored for 3 months and 17/21 were quantifiably stable after 5 months when stored at 4 °C.

Achieving routine application of dried blood spots for erythropoietin receptor agonist analysis in doping control: low-volume single-spot detection at minimum required performance level

Background: Erythropoietin receptor agonists (ERAs) are substances prohibited in sports and currently monitored in urine and blood. There is a great interest in new matrices like dried blood spots (DBSs). Method: A direct method for the detection of ERAs in DBSs using one single spot of 25 μl has been optimized and validated. Results: Limits of detection close or equal to those required by the World Anti-Doping Agency for serum/plasma samples were achieved, using a volume 20-times lower. All analytes were stable for at least 90 days at room temperature. Conclusion: Method performance was comparable to the requirements established for blood samples and, thus, monitoring of ERAs is reliable in DBSs in the context of doping control.

Blood microsampling technologies: Innovations and applications in 2022

With the development of highly sensitive bioanalytical techniques, the volume of samples necessary for accurate analysis has reduced. Microsampling, the process of obtaining small amounts of blood, has thus gained popularity as it offers minimal-invasiveness, reduced logistical costs and biohazard risks while simultaneously showing increased sample stability and a potential for the decentralization of the approach and at-home self-sampling. Although the benefits of microsampling have been recognised, its adoption in clinical practice has been slow. Several microsampling technologies and devices are currently available and employed in research studies for various biomedical applications. This review provides an overview of the state-of-the-art in microsampling technology with a focus on the latest developments and advancements in the field of microsampling. Research published in the year 2022, including studies (i) developing strategies for the quantitation of analytes in microsamples and (ii) bridging and comparing the interchangeability between matrices and choice of technology for a given application, is reviewed to assess the advantages, challenges and limitations of the current state of microsampling. Successful implementation of microsampling in routine clinical care requires continued efforts for standardization and harmonization. Microsampling has been shown to facilitate data-rich studies and a patient-centric approach to healthcare and is foreseen to play a central role in the future digital revolution of healthcare through continuous monitoring to improve the quality of life.

DropWise: current role and future perspectives of dried blood spots (DBS), blood microsampling, and their analysis in sports drug testing

For decades, blood testing has been an integral part of routine doping controls. The breadth of information contained in blood samples has become considerably more accessible for anti-doping purposes over the last 10 years through technological advancements regarding analytical instrumentation as well as enhanced sample collection systems. Particularly, microsampling of whole blood and serum, for instance as dried blood spots (DBS), has opened new avenues in sports drug testing and substantially increased the availability and cost-effectiveness of doping control specimens. Thus, microvolume blood specimens possess the potential to improve monitoring of blood hormone and drug levels, support evaluation of circulating drug concentrations in competition, and enhance the stability of labile markers and target analytes in blood passport analyses as well as peptide hormone and steroid ester detection. Further, the availability of the fraction of lysed erythrocytes for anti-doping purposes warrants additional investigation, considering the sequestering capability of red blood cells (RBCs) for certain substances, as a complementary approach in support of the clean sport.

Detection of erythropoiesis stimulating agent Luspatercept after administration to healthy volunteers for antidoping purposes

Luspatercept (Reblozyl®) is a newly approved anti-anemic drug prohibited by the World Anti-Doping Agency. It promotes erythropoiesis by limiting apoptosis of immature erythroblasts and the risk of misuse by athletes for doping is high. Proposed detection methods have been published recently but only evaluated in vitro. The objective of this study was to perform the first administration of luspatercept in healthy volunteers for antidoping purpose and to evaluate the detectability in serum, dried capillary blood spots (DBS, collected using TASSO M20 device), and urine. Indirect detection was also evaluated by analyzing hematological parameters for the Athlete Biological Passport. Four volunteers (two males, two females) received one subtherapeutic dose of luspatercept (0.25 mg/kg) followed 3 weeks after by a second dose. Samples were collected from before administration until 7 weeks after the second dose. After immunopurification, electrophoretic separation SDS-/SAR-/IEF- polyacrylamide gel electrophoresis (PAGE), and immunodetection, luspatercept was detected at high levels in serum until the end of the collection, sign of a very slow elimination and similarly detected unchanged at lower levels in urine from 2 days after the first administration until 7 weeks postadministration. DBS showed also the same long window of detection. Luspatercept effects were however of limited amplitude on hematological markers, and only two subjects presented atypical points outside the physiological limits during the study. The direct detection method was very efficient, and change of electrophoretic method and detection antibody can be used for confirmation of suspicious samples.

Optimizing detection of erythropoietin receptor agonists from dried blood spots for anti-doping application

The World Anti‐Doping Agency (WADA) has recently implemented dried blood spots (DBSs) as a matrix for doping control. However, specifications regarding the analysis of the class of prohibited substances called erythropoietin (EPO) receptor agonists (ERAs) from DBSs are not yet described. The aim of this study was to find optimal conditions (sample volume and storage) to sensitively detect endogenous erythropoietin (hEPO) and prohibited ERAs from DBSs and compare detection limits to WADA‐stipulated minimum required performance levels (MRPLs) for ERAs in serum/plasma samples. Venous whole blood was spotted onto Whatman 903 DBS cards with primarily 60 μl of blood, but various volumes from 20 to75 μl were tested. All samples were immunopurified with MAIIA EPO Purification Gel kit (EPGK) and analysed with sodium N‐lauroylsarcosinate polyacrylamide gel electrophoresis (SAR‐PAGE) and Western blot. Sixty‐microliter DBSs allowed the detection of the four main ERAs (BRP, NESP, CERA and EPO‐Fc) at concentrations close to WADA's MRPLs described for 500 μl of serum/plasma. Different storage temperatures, from −20°C to 37°C, were evaluated and did not affect ERA detection. A comparison of the detection of endogenous EPO from the different anti‐doping matrices (urine, serum and DBSs produced from upper arm capillary blood) from five participants for 6 weeks was performed. Endogenous EPO extracted from DBSs showed intra‐individual variations in male and female subjects, but less than in urine. Doping controls would benefit from the stability of ERAs on DBSs: It can be a complementary matrix for ERA analysis, particularly in the absence of EPO signals in urine.

Monitoring of hemoglobin and erythropoiesis-related mRNA with dried blood spots in athletes and patients

Aim: We assessed the feasibility of using hematological parameters (such as hemoglobin and reticulocyte mRNA) in dried blood spot (DBS) samples to test athletes for doping and to improve patient care. Methods: Hemoglobin and erythropoiesis-related mRNAs were measured in venous blood and DBSs from both healthy athletes and hemodialysis patients. Results: We accurately measured hemoglobin changes over time in both venous blood and DBS samples. Combining hemoglobin and mRNA analyses, we detected erythropoietin injection in DBSs more sensitively and with higher efficiency by using the DBS OFF-score than by using the athlete biological passport OFF-score. Conclusion: DBS-based measurements are practical for calculating hemoglobin levels and athlete biological passport OFF-scores. This approach may help detect blood doping and help predict patient response to EPO.

Annual banned-substance review: Analytical approaches in human sports drug testing 2020/2021

Most core areas of anti-doping research exploit and rely on analytical chemistry, applied to studies aiming at further improving the test methods' analytical sensitivity, the assays' comprehensiveness, the interpretation of metabolic profiles and patterns, but also at facilitating the differentiation of natural/endogenous substances from structurally identical but synthetically derived compounds and comprehending the athlete's exposome. Further, a continuously growing number of advantages of complementary matrices such as dried blood spots have been identified and transferred from research to sports drug testing routine applications, with an overall gain of valuable additions to the anti-doping field. In this edition of the annual banned-substance review, literature on recent developments in anti-doping published between October 2020 and September 2021 is summarized and discussed, particularly focusing on human doping controls and potential applications of new testing strategies to substances and methods of doping specified in the World Anti-Doping Agency's 2021 Prohibited List.