All 166 riders left in the Tour de France underwent an anti-doping test on Monday evening, Cycling Weekly can reveal.A day after Tadej Pogaar (UAE Team Emirates-XRG) and Jonas Vingegaard (Visma-Lease a Bike) were woken up in the early hours of Sunday morning by doping control officers (DCO), every other bike rider in the race was visited by a DCO on behalf of the International Testing Agency (ITA) on Monday and made to provide a blood sample. They were also made to do so two days before the race started in Barcelona.Riders were tested between 8 and 11pm on Monday, inside standard testing hours. In a statement to CW, the ITA said: The International Testing Agency confirms that a comprehensive blood Athlete Biological Passport (ABP) testing mission was carried out during the Tour de France rest day. All riders in the peloton were included in the operation, which forms part of the ITAs ongoing intelligence- and risk-based anti-doping program for the race. This mission complements the standard pre-competition testing conducted on all riders in the days preceding the Grand Dpart and any test already conducted during the race. Collecting additional blood samples enables the ITA to assess variations in relevant haematological biological markers and strengthen the longitudinal monitoring of each riders individual profile.The Athlete Biological Passport does not seek to detect a prohibited substance or method directly. Instead, it monitors selected biological variables over time to identify changes that may indicate the effects of doping and inform further anti-doping action. Cycling was among the first sports to introduce the Athlete Biological Passport, launching its program in 2008, and the ABP has since become a central component of anti-doping programs across international sport.Cycling Weekly has verified that riders from five teams, including Pogaar and the now-at-home-and-injured Vingegaard, have so far received unannounced anti-doping tests between 11pm and 6am, which require authorisation from a judge. Cycling Weekly knows of at least one rider being tested at 5am during the first week, meaning that Pogaar and Vingegaard were not the first riders to be subjected to a test in the early hours.Only the ITA and no other body has requested permission to test a select number of riders during the night. To have the authorisation confirmed, the ITA has had to prove to judges that there is sufficient doubt and scepticism surrounding a rider. They can point to a number of factors, including but not limited to abnormalities in a riders ABP, a sudden upturn in performances and results, or a tip-off.The ITAs approach at this Tour has been described as strange by Pogaar and criticised by many, including the riders union, the CPA. Cycling Weekly understands that though the ITA accepts that night-time testing is invasive and disrupts a riders sleep, its essential to their intention of being unpredictable. It also aids their efforts to detect possible cases of micro-dosing.Benjamin Cohen, the ITAs director general, signposted these nighttime tests back in April when speaking with The Athletic. Do we need to change when we test and how we test? Cohen asked. If you go and speak to the [ITA] testing department, they would say: yes, we need to be able to test whenever we can. Certainly, based on information [the ITA has], it would suggest that there is an issue [with micro-dosing].I dont think you would want to do mass testing at the Tour de France, for example, and wake up all the athletes at 3am that doesnt make sense. I think you would need to have very concrete suspicions [about an athlete] and use that in a very cautious manner. I wouldnt advocate for mass night testing, but certainly for some flexibility if you believe that there is an issue.