Anti-Doping Detection Evidence
How laboratory testing differs from a concentration curve.
A drug half-life cannot establish a negative-test date.
The previous calculator showed estimated windows and calendar dates without adequate supporting evidence. Those outputs have been withdrawn. Use this reference to understand the measurements and assess a detection claim.
Three different questions
- Blood concentration
- A concentration curve models a drug under absorption and elimination assumptions. It does not establish a laboratory result. Read the model methodology.
- Analytical detection
- A method may target the substance, a metabolite, or another marker in a particular sample type. WADA specifies method and reporting requirements; see TD2022MRPL, sections 1–5.
- Prohibited status
- The rules determine which substances and methods are prohibited, and when. A model cannot establish eligibility to compete. Consult the official WADA Prohibited List.
Testosterone: a profile and an origin question
Urinary steroid concentrations and their ratios form a steroid profile. Repeated samples contribute to the steroidal Athlete Biological Passport. This is more information than a single blood testosterone value. WADA TD2021EAAS v2.0, sections 1.1–1.2.
Carbon-isotope ratio analysis (GC/C/IRMS) compares selected steroids with reference compounds to assess their origin. It may be requested even when steroid-profile markers fall within normal ranges. WADA TD2022IRMS v1.0, sections 1.1.1 and 2.0.
Read the testosterone detection evidence guideBefore relying on a quoted detection duration
- Find the original study and the exact substance or marker measured.
- Check the sample type, analytical method, and the study's definition of a detected result.
- Read the formulation, exposure, participants, and sampling schedule actually studied.
- Check whether sampling ended while results were still positive. The final observation does not establish what an uncollected later sample would have shown.
A minimum required performance level (MRPL) is a laboratory capability requirement, not a universal detection limit or reporting cutoff. WADA permits findings below an MRPL; separate reporting provisions apply to some substances. TD2022MRPL v1.1, sections 1, 2 and 5.
Use the rules that apply to your situation
The 2026 WADA List, effective 1 January 2026, places anabolic agents in section S1, prohibited both in and out of competition. Confirm current requirements with the responsible anti-doping organization. Discuss prescribed treatment and any therapeutic-use-exemption requirements with your clinician and that organization; do not change treatment based on a detection estimate.
This page explains evidence. It does not predict an individual's test result, provide a testing deadline, or determine eligibility to compete.
Source versions checked 5 October 2026. Use WADA's current publication pages when checking later rule or laboratory-document changes.
About this tool
This reference explains how analytical detection differs from a pharmacokinetic curve, how to read the scope of a detection study, and where to find current anti-doping requirements. It does not turn a half-life, stored range or last-dose date into a prediction of a negative test.
How to use it
- 1 Distinguish blood concentration, analytical detection and prohibited status.
- 2 Check the original study's substance or marker, sample type, method, participants, exposure and sampling period.
- 3 Keep the study's observation limits attached to any quoted result.
- 4 Use the linked official documents and the responsible anti-doping organization for current requirements.
Frequently asked questions
Can a drug half-life predict when an anti-doping test will be negative?
No. A concentration model does not establish what a particular assay will detect in a particular sample. Multiplying a parent-drug half-life cannot supply a universal detection duration or testing deadline.
Does the last positive sample in a study establish the maximum detection time?
No. It describes an observed result under that study's conditions. If later samples were not collected, the study does not establish when a later result would become negative.
Is a minimum required performance level a universal detection cutoff?
No. WADA's MRPL is a laboratory capability requirement, not a universal detection limit or reporting cutoff. The technical documents distinguish MRPLs from other reporting provisions and permit findings below an MRPL.
Educational use only — not medical advice.