The star was arrested by Swedish police after his car was pulled over in a roadside control late on Saturday night. Earlier in the evening he had given a concert in the university town of Uppsala, north of Stockholm.
He was then taken to the police station for a urine test.
On Friday it emerged that the rapper tested positive for narcotics in an initial drug test.
“Suspicion that a person is under the influence of drugs sometimes arises when the police are talking to a person,” said Christer Nordström, a spokesman for Uppsala police, when he explained the process to The Local.
“They are then taken to the station for a physical examination, that is, they have to leave a urine sample.
“You then use a screening tool called a multi-drug screen test which, after a few seconds, shows a certain colour and a number of test lines.
“Two lines indicate that the sample is negative and the case is dropped, whereas one line shows that there are traces of something, which results in a suspicion of crime.”
However, Nordström emphasized that the test is not conclusive enough in itself and the police will have to wait for the lab test, which could take a few weeks.
“If the lab test turns out to be positive, a decision will have to be made then and it will be in the hands of the prosecutor,” he said.
The rapper took to Twitter to express his anger at the drug tests on Sunday, vowing that he would never return to the Nordic country.
“2 all my Sweden fans U can blame YA police dept for never seeing me again in your beautiful country,” the rapper wrote in a tweet.
2 all my sweden fans U can blame YA police dept for never seeing me again in your beautiful country… https://t.co/B9bMVP1R1i
— Snoop Dogg (@SnoopDogg) July 26, 2015
The singer also hit out at Swedish police, complaining that the arrest was due to racial profiling, which police were quick to deny.
“No, we don't work like that. That's just nonsense. We completely reject the notion that being stopped for a control would be down to racist thoughts. It's not about that,” Nordström told the Aftonbladet tabloid at the time.
Snoop Dogg's song lyrics often display his fondness for marijuana and he has previously had run-ins with police elsewhere over the drug.
Sweden has by and large a 'zero tolerance' approach to drugs, although calls for legalizing the drug are sometimes heard. The Nordic country criminalized illicit drug use in 1988, following a two-year attempt to introduce a more tolerant approach that was considered a failure by authorities.
Anyone suspected of being 'high' can be detained and given a compulsory urine test. If positive, they are slapped with a criminal charge and must stand trial.
According to figures released by the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) last year, only nine percent of the Swedish school population has tried cannabis, compared to 39 percent in France, 42 percent in the Czech Republic and around 25 percent in Britain, Belgium and the Netherlands.
The Local has contacted Snoop Dogg for comment.
Interview by Elin Jönsson.