Longitudinal Profiling of Endogenous Steroids in Blood Using the Athlete Biological Passport Approach

Area of Science:

• Sports Science
• Anti-Doping
• Biochemistry

Background:

• The Athlete Biological Passport (ABP) has improved detection of endogenous anabolic androgenic steroids (EAAS) like testosterone (T) in urine.
• Current methods may not effectively detect EAAS in individuals with low urinary biomarker excretion.

Purpose of the Study:

• To enhance anti-doping strategies for EAAS by incorporating blood analysis for new target compounds.
• To evaluate the effectiveness of the ABP's Steroidal Module using blood-based testosterone and T/androstenedione (T/A4) markers.

Main Methods:

• Utilized 4 years of anti-doping data to establish T and T/A4 distributions as priors.
• Analyzed individual profiles from two testosterone administration studies in male and female subjects.
• Evaluated a longitudinal ABP-based approach using serum samples for T and A4.

Main Results:

• An ABP approach with 99% specificity identified all females during transdermal T application and 44% of subjects three days post-treatment.
• Testosterone (T) demonstrated the highest sensitivity (74%) for detecting transdermal T application in males.
• The T/androstenedione (T/A4) ratio also proved valuable in the ABP framework.

Conclusions:

• Including T and T/A4 markers in the ABP Steroidal Module significantly improves the detection of testosterone administration.
• This enhanced approach is especially effective for identifying transdermal testosterone application, particularly in female athletes.
• Blood analysis offers a complementary strategy to urine analysis for comprehensive anti-doping efforts.