WINFIELD, W.Va. -- Questions linger over Putnam County Schools' new, costly, controversial and relatively rare policy to test middle and high school students for drugs by swabbing their saliva.
Some wonder if saliva tests are as effective as urine tests, which school board members had originally planned to implement but nixed in favor of the less-intrusive saliva swab. Experts, though, say saliva tests are just as foolproof as urine tests, if administered correctly.
"Lab-based oral fluid testing has been proven to be as good as urine testing for all the drugs," said Dr. Todd Simo, director of medical services for the drug-testing agency HireRight. "The positive rates between the two are almost exactly identical."
Good results hinge on test administrators following directions to the letter, Simo said. That includes making sure the test taker hasn't had so much as a Tic Tac in his mouth for at least 10 minutes.
Virtually any substance can dilute the test taker's saliva and distort lab results.
Some test-takers have tried crazier-sounding remedies, like gargling peroxide or bleach before an administrator inserts the swab.
"I don't know how long you're going to keep bleach in your mouth," Simo said. "but these hammerheads can do some stupid things."
Even water is probably just as effective at washing away traceable amounts of marijuana, cocaine, alcohol and other drugs from the saliva glands, Simo said. After 10 minutes, though, the saliva glands should have regenerated enough uncontaminated saliva to yield an accurate result, he said.
The general problem with the oral swab is that drugs are traceable in saliva for a very short time, compared to urine.
"The reality is that, if the kid is going to smoke dope on Friday night, he won't test positive on Monday," said Dr. Michael Walsh, president of the Walsh Group, a Maryland-based firm that specializes in toxicological research.
The saliva swab window lasts about 24 hours for marijuana and most methamphetamines, Walsh said. Those drugs dissipate from the user's saliva after that time, which makes the saliva test less than ideal for school students, he said.
Police generally use the saliva swab to test recent drug use in DUI suspects, Walsh said. Even then, the tests are sometimes tough to administer because those drugs often give the user dry-mouth, he said.
The other problem with mouth swabs is that on-site preliminary screens are largely ineffective at detecting traces of marijuana in the saliva. Both Simo and Walsh say that on-site testing devices are virtually useless at yielding accurate results for the drug.
"It's not the kind of thing anyone should base an employment decision on," Simo said. "It's not the type of thing they should make a school-based decision on either."
On-site testing devices cannot detect high enough quantities of THC, marijuana's main ingredient, in the saliva, Simo said. Administrators should always take specimens to a lab for a more thorough test, at which point the accuracy rate is just as high as urine tests, he said.
Walsh found in one of his studies that on-site test kits missed 60 percent of the marijuana users that a follow-up lab test caught. Tests for methamphetamines and amphetamines, like crystal meth and speed, do not fare much better. On-site tests missed about 20 percent of those users, Walsh said.
"If you do an on-site oral fluid test you're not going to have a lot of positives," he said, "but you're kind of sticking your head in the sand."