An athlete biological passport is an individual, electronic record for professional athletes, in which profiles of
Although the terminology athlete passport is recent, the use of biological markers of doping has a long history in anti-doping. Maybe the first marker of doping, that tries to detect a prohibited substance not based on its presence in urine or blood, but through the induced deviations in biological parameters, is the so-called testosterone over epitestosterone ratio (T/E). The T/E has been used by sports authorities since the beginning of the 1980s to detect
The athlete passport received a lot of attention when its blood module was established at the beginning of the 2008 racing season by the UCI.
 In May 2008 they revealed that 23 riders were under suspicion of doping following the first phase of blood tests conducted under the new biological passport.
 The blood module of the athlete passport aims to detect any form of
According to the World Anti-Doping Agency, the athlete biological passport is administered to establish whether an athlete is manipulating his/her physiological variables without detecting a particular substance or method. The biological passport uses the standardized approach of urine sampling to determine steroid abuse. The objective of this testing is to identify athletes in a haematological module and a steroidal module.
The haematological module tests for certain markers in the body that identify the enhancement of oxygen transport. The specific markers the module tests for include haematocrit, haemoglobin, red blood cell count, percentage of reticulocytes, reticulocytes count, mean corpuscular volume, mean corpuscular haemoglobin, mean red cell distribution width, and immature reticulocyte fraction.
The steroidal module collects information on markers for steroid doping and aims to identify endogenous anabolic androgenic steroids. The specific markers the module tests for include testosterone, epitestosterone, the testosterone/epitestosterone ratio, androsterone, and etiocholanolone. 
The World Anti-Doping Agency recently released the 2014 Prohibited Substances list and it will take effect on 1 January. In the new list, the agency modified the definitions of exogenous and endogenous steroids being tested for in the steroidal module of the biological passport.