Former world number 12 Troicki, 27, was asked to provide samples during the Monte Carlo Masters on April 15, where he lost in the first round to Jarkko Nieminen.
The world number 53 did provide a urine specimen but said he was unwell and could not give a blood sample. Troicki told the ITF tribunal that the doping control officer told him the urine sample would be sufficient.
But the ITF tribunal decided that the officer had given no such assurance and that the player had breached Article 2.3 of the Tennis Anti-Doping Programme (refusing or failing without compelling justification to submit to sample collection).
The tribunal did accept that Troicki was under stress at the time of the test and that this mitigating factor reduces the length of his ban from two years.
The ban will expire on midnight of January 24 2015.
Troicki actually played on Thursday, losing 6-0 6-4 to Tommy Robredo at the Croatian International tournament in Umag.
The 2010 Davis Cup winner's results, ranking points and prize money from Monte Carlo were also forfeited.
Troicki, from Belgrade, has only won one career ATP title - in Moscow three years ago - but his overall consistency means he was in and around the top 20 between 2011-12.
This season he hovered around the top 40-50, and this blow could signal an untimely blow to the career of Serbia's number three player.