Spring Break
Forensics expert explains marijuana testing myths
Brenna McCabe
Issue date: 4/10/07 Section: News
Marinol can be prescribed for everything from arthritis to intense muscle pain as an off label prescription, he said.
According to state law, individual caretakers or patients in Rhode Island are allowed the equivalent of 2.5 ounces of usable marijuana after being approved through an extensive screening process provided by the state health department. Because of an increase in medical marijuana laws and research, ElSohly's research team developed a way to separate true medical marijuana users from arrested individuals who were using it to get out of trouble.
Researchers found that a variation of THC called tetrahydrocannabivarin, or THCV, is only found in human samples after one has smoked a marijuana cigarette or ingested it in baked form.
"We had to show that THCV would not come out even if you smoked Marinol," he said. "Marijuana cigarettes contain both THCV and THC. With the others, there's nothing. We've been able to prove that THCV is only excreted in human urine as a result of the ingestion of a product containing THCV, which is not the result of smoking or orally ingesting Marinol. This has become standard."
Currently, the most common types of drug testing for employers and police include taking urine and blood samples. However, ElSohly said that some places differ, and may use oral fluids or screen in different ways.
"There can be physical deposits in the mouth if you smoke a marijuana cigarette," he said, explaining the process of testing oral fluids. "[If done this way], it requires very sophisticated testing. Nevertheless, it's being used as an option."
ElSohly said there are pros and cons to each type of drug testing, even blood tests. Though testing for marijuana through blood can be good because blood provides a constant volume, when being pulled over after smoking, sometimes time works against the test. "The problem is, you hit somebody [while driving after smoking] and it's usually an hour before … It's not enough THC in the blood to be positive on a drug test," he said.
According to state law, individual caretakers or patients in Rhode Island are allowed the equivalent of 2.5 ounces of usable marijuana after being approved through an extensive screening process provided by the state health department. Because of an increase in medical marijuana laws and research, ElSohly's research team developed a way to separate true medical marijuana users from arrested individuals who were using it to get out of trouble.
Researchers found that a variation of THC called tetrahydrocannabivarin, or THCV, is only found in human samples after one has smoked a marijuana cigarette or ingested it in baked form.
"We had to show that THCV would not come out even if you smoked Marinol," he said. "Marijuana cigarettes contain both THCV and THC. With the others, there's nothing. We've been able to prove that THCV is only excreted in human urine as a result of the ingestion of a product containing THCV, which is not the result of smoking or orally ingesting Marinol. This has become standard."
Currently, the most common types of drug testing for employers and police include taking urine and blood samples. However, ElSohly said that some places differ, and may use oral fluids or screen in different ways.
"There can be physical deposits in the mouth if you smoke a marijuana cigarette," he said, explaining the process of testing oral fluids. "[If done this way], it requires very sophisticated testing. Nevertheless, it's being used as an option."
ElSohly said there are pros and cons to each type of drug testing, even blood tests. Though testing for marijuana through blood can be good because blood provides a constant volume, when being pulled over after smoking, sometimes time works against the test. "The problem is, you hit somebody [while driving after smoking] and it's usually an hour before … It's not enough THC in the blood to be positive on a drug test," he said.
