Troicki had originally been suspended for 18 months by an International Tennis Federation anti-doping tribunal but had appealed to CAS to have the sanction overturned.
Troicki refused to take a blood test at the Monte Carlo Masters in April because he was feeling unwell and has a severe phobia of needles.
The player has always maintained the doping control officer (DCO) had assured him he would not face punishment.
On Tuesday, the Court of Arbitration for Sport ruled the Serbian should serve a 12-month ban for missing a doping test.
The CAS panel accepted the DCO should have made sure he understood the gravity of the situation but found he had committed a doping offence.
Compatriot Novak Djokovic has been one of Troicki's most vocal supporters and he gave an emotional and angry response to the verdict after beating Roger Federer at the Barclays ATP World Tour Finals on Tuesday.
The world number two branded Troicki's suspension, which runs until July 2014, "a total injustice" and said he has lost all trust in the system.
Troicki told CNN World Sport: "I read (Novak's) statement late in the evening, and I didn't actually know that he was going to say that - and the way he said it really meant the world to me.
"I have to agree (about the system) as it happened to me. I am the victim.
"We all agree that anti-doping is necessary. We believe our sport is clean but my case, I really feel there's been a lot of errors.
"I'm the one who is suffering for being unable to play for one year. And it's not just one year but also I'll be starting from zero because I will lose all my (ranking) points. And that is the toughest part of it.
"It's definitely the worst time for me. A lot of errors have been made and the court agrees on those errors. But 12 months is the smallest time I could get by the rules."
Troicki had hoped he would be cleared by CAS in time to play in the Davis Cup final between Serbia and the Czech Republic later this month in Belgrade.
He said: "It's going to be a very tough moment for me. I was here for the semi-finals, when Serbia was playing against Canada in Belgrade, and I wasn't even allowed in the arena.
"They said it was not possible for me to attend, to be a spectator who bought a ticket and attended the match. I have been treated like a criminal."
Asked for his opinion about the case in London, world number one Rafael Nadal gave qualified support to Troicki.
The Spaniard said: "We have rules. We can like them (or think they're) bad rules, but we have rules.
"I am very sorry for Viktor because I believe 100% in him. Probably the doctor (DCO) made a mistake.
"But at the end he knows that he has to do the control when the authorities required. So it was a big mistake."