Just mentioning a drug test can send chills down the spine of many college students looking for jobs or internships.
Everything from alcohol to designer drugs can be detected through urine and hair analysis -- even through saliva. Drug analysis tests not only for drugs currently present but also drug metabolites, components which the body breaks the drug into after digestion.
Each different drug test shows a specific time period of drug use, and saliva has the shortest time line.
"The whole idea is [that saliva testing] is non-invasive, inexpensive and instant," said Douglas Granger, director of Penn State's Bio-behavioral Endocrinology Laboratory. "It can test for drugs used within the past 24 hours."
An advantage of saliva testing would be the ease of testing DUI suspects on sight. Granger said saliva can be used not only to screen for drug use but also possible health risks such as HIV and cancer. Saliva testing is not approved by the Food and Drug Administration (FDA), and Granger said he has not recently heard an update on the progression toward FDA approval. Ethical issues of privacy and random testing are inhibiting the process, he said.
Fill it up
Gloria Martz of Centre Community Hospital said the hospital does drug screening for local businesses.
"We test basically just urine specimens, we don't have the type of equipment to screen hair," Martz said. "We do not test for steroids; our main concern is legality and treatment options. For examples, DUIs or when a patient is admitted to the [emergency room]."
Urine tests involve two specific screenings. The first test, immunoassay, uses specific antibodies or proteins, which attract drug metabolites present in a user's urine. The amount of metabolites, which bond with antibodies, is proportional to the amount of drug present in the urine. All positive results are confirmed by gas chromatography/mass spectrometry screening. In this, the bonded metabolites are extracted from the urine and injected into a machine that identifies the drug and amount present. Both tests are necessary because of the slightly higher error margin of the immunoassay test.
After two to four days, most substances, such as heroin and cocaine, are not detectable by urine screening. Traces of marijuana, however, can stay in the system for weeks, depending of the frequency of use. The heavier the drug use, the more time the drug will take to leave the body
Urine analysis has other disadvantages such as the invasive nature of the procedure and the ability of applicants to beat the test. By diluting urine through drinking a large amounts water, the concentration of the drug is lowered, but still detectable in some cases. There are also numerous Web sites that claim to offer drinks, chemicals and masking agents that will flush the body of drug metabolites, making a negative test result.
Charles Yesalis, professor of kinesiology and health policy and administration, said urine is the most accurate test for steroids. Yesalis concentrates mostly on developing procedures for testing Olympic athletes.
"We can only test for drugs that we know exist," he said. "Athletes can custom design a drug which may be slightly different from testosterone, the common factor in most performance drugs, and it would not be detected."
Taken from anywhere
Hair drug testing can provide a historical background of drug use for up to three months. Traces of drug metabolites become trapped in the core of the hair after usage, and cannot be washed, dyed or flushed out, said Daniel Jones, senior scientist and director of the Intercollegiate Mass Spectrometry Center. A hair specimen can show whether a drug has been used regularly or abstained from for a period of time. Drug metabolites can be detected in the new growth of hair for up to 90 days.
"The 90-day cut off depends on the drug and on the individual," Jones said. "If you let things go for more than three months, the drug could still be present but most likely the drug metabolites have degraded."
A small amount of hair -- about 60 hairs or the size of a pen tip -- is needed for analysis. Since the drug metabolites are only detected in new hair growth, sample hair must be taken from the root. Hair can be taken from anywhere on the body for analysis. About one and a half inches of hair from the root is needed for testing.
The most important thing is extracting the drug from hair, Jones said. Some tests use enzymes to partially digest hair, allowing access to the drug at the core. The initial tests are trying to liquefy the sample in order to be sent for analysis. Jones said criminal cases involving drug tests use hair analysis in forensic crime labs.
Radioimmunoassay tests use radioactive tags. If the drug is present in the sample it will bind to antibodies, which will then release radioactive waves. The measure of the radioactive material released is the amount of drug present as well as the type.
"Hair gives you a longer time frame because metabolites in the core break down very slowly, as opposed to urine, which is a different snapshot, one of what has been done recently," Jones said.
And just as Web sites offer masking agents for urine tests, products are offered which coat hair, causing a reaction when hair is tested resulting in a negative outcome.
Being around marijuana smoke can result is in a positive test, but after an initial test, a more intense test is done as confirmation. The amount of exposure determines the outcome of the test. As far as absorption by the hair, Jones is skeptical.
"Drugs can be absorbed into the hair but there is a good chance that it will be washed off and not affect a test," Jones said.
Beat the test?
"Anyone who is clever can find ways for a test to give a positive result," Jones said. "There is almost an entire science based on deceiving drug tests, but generally the lab tests are reliable."
Edward Rosick, a physician at University Health Services agreed with Jones. He said most products do not work because drug tests today are quite specific and sensitive. The products that claim to mask drugs will only add other substances to the body to try to confuse the test, he said.
Jones said there are several stages of drug testing, and, "it's not a perfect technology; there are errors that can be made and specimens can be contaminated. Anything that comes up negative will not go on to subsequent testing but positive results will go on to the next step to confirm the results."
