Reporting and managing elevated testosterone/epitestosterone ratios--novel aspects after five years' experience

Area of Science:

• Sports Science
• Anti-Doping
• Biochemistry

Background:

• The testosterone/epitestosterone (T/E) ratio is used to detect exogenous testosterone administration.
• The established T/E ratio threshold was lowered from 6 to 4 in 2005.
• Limitations of the T/E ratio include UGT2B17 polymorphism.

Purpose of the Study:

• To evaluate the efficiency of the current T/E ratio threshold for detecting testosterone doping.
• To propose improvements for more effective testosterone misuse detection.

Main Methods:

• Analysis of 63,510 doping control urine samples between 2005 and 2009.
• Testing specimens with T/E ratio > 4 using isotope ratio mass spectrometry (IRMS).
• Comparison of IRMS results with T/E ratio values and athlete steroidal profiles.

Main Results:

• 1442 specimens (2.3%) had a T/E ratio > 4, with 80 (5.5%) testing positive by IRMS.
• Lowering the threshold to 4 resulted in a low positive rate (0.4%) for T/E ratios between 4 and 6.
• High T/E ratios showed a greater probability of exogenous testosterone confirmation via IRMS.

Conclusions:

• The current T/E ratio threshold of 4 has marginal efficiency in detecting testosterone doping.
• Implementing individual reference ranges and increasing the T/E ratio threshold to 6 for obligatory IRMS analysis is recommended.
• Additional markers like suppressed luteinizing hormone (LH) levels in males could enhance detection strategies.