2. Test Methods
There are six types of tests that you should be aware of:
Before continuing, I must say that this text mainly applies to urinalysis. However, I try to cover all methods for beating drug tests.
It would be helpful if people could somehow find out which test they are getting ahead of time. Though caution must be taken. Asking your boss whether you're getting an EMIT or GC-MS would imply that you know too much, or seem too curious. The law doesn't protect you from unjust hiring practices, and your boss to be may refuse you employment for any reason. If simply drinking a cup of water makes the boss feel uncomfortable, the verdict may be guilty before you even take the test.
2.1 Substances That Are Detectable
An assay can be developed for any drug using GC-MS. The table below indicates what can be dectected in screening tests.
|D = Detectable|
|ND = Not Detectable|
2.2 Gas Chromatography (GC)
Gas-liquid chromatography (GLC), or simply gas chromatography (GC), is a chemical analysis instrument that separates illicit chemicals in a test sample.
2.3 Gas Chromatography-Mass Spectrometry (GC-MS)
Gas chromatography-mass spectrometry (GC-MS) is a method that combines the features of gas-liquid chromatography and mass spectrometry to identify illicit substances in a test sample. GC-MS is a two-step process, where gas chromatography (GC) separates the sample into its constituent parts, while mass spectrometry (MS) provides the exact molecular identification of the compounds.
Compounds are separated by GC and are the introduced, one at a time, into a mass spectrometer. As the sample constituents enter the MS, they are bombarded by electrons, which cause the compound the break up into molecular fragments.
The fregmentation patters is reproducible and characteristic, and is considered the "molecular fingerprint" of a specific compound.
Gas chromatography-mass spectrometry is considered to be the most definitive method for confirming the presence of a drug in the urine and is approximately 100 to 1,000 times more sensitive than TLC. Selective ion monitoring has been used to improve the GC-MS results. This procedure is the most costly, averaging approximately $200 per sample to test.
The GC-MS is typically used to confirm "positive" EMIT test results. GC-MS will indicate precisely what chemical is present. This is necessary because the EMIT will only indicate whether something similar to what's being tested was found. The GC-MS is difficult and more costly, which is why the EMIT is given first.
Abstinence and substitution are the only ways to defeat the GC-MS test. GC-MS is very precise when done right. However, it's still subject to human error. For example, if the equipment isn't cleaned well, the previous test sample could get mixed with the next sample. According to Dr. Edward Cone, the GC-MS is 99% accurate, which is not very accurate on a large scale when you realize that 10,000 out of every 1,000,000 will get false results. Read more about test accuracy and standards.
2.4 Hair Testing
When THC metabolites are in the blood, they go through the blood vessels in the head, and get filtered through the hair. THC metabolites remain in the hair as a permanent record. The hair test costs several hundred dollars and is rarely given because urinalysis is cheaper and more accurate.
Hair tests are widely used throughout the casino industry. They cut 50 strands of hair from the scalp, and send it in to the testing lab where they liquefy it. A hair sample is dissolved in a series of solvents which extract the drug metabolites and then are analyzed via GC-MS. It can take several hours to days just to extract metabolites.
Average hair grows 1/4 inch per month. Typically they just use hair that is 1-1/2 inches from the scalp, though some labs will take enough to test for up to 3 years. The liquid is run through the most sensitive GC-MS machines available, and can detect as little as 1 ng/mL! The hair test discriminates in that detection is easier in dark hair.
Colored people may be discriminated against further because melanin is in their hair, which can be mistaken for THC. However, there is conflicting data as to whether melanin can be detected as THC. Psychemedics Corporation has a PDT-90 kit for $59.95. This home test kit is for parents that want to chop off a lock of their child's hair to find out what drugs he or she is using.
Beating the hair test is extremely hard, and there are false positives. Bleaching or dying your hair is rumored to work, but it doesn't. I imagine you can shave every hair on your body and claim that you're a swimmer.
According to NORML, Aloe Rid by Nexus is a shampoo that will aid in testing negative. Aloe Rid is available only in salons. Healthy Hair, from Sampson Health Products, is another shampoo designed to beat the hair test. Healthy Hair is sold in retail stores throughout Las Vegas. Keith Thrash from Sampson Health Products recommends pre-cleansing with Aloe Rid prior to using Healthy Hair. Healthy Hair is used in the morning and before going to bed. Each session takes 20 minutes. According to Steve at Sampson Health Products, two out of a thousand people failed the hair test when using Healthy Hair.
Byrd Labs is currently developing a shampoo to defeat the hair test. Some have suggested treating hair with oil because THC is oil based and oil soluble. However, there is no proven way to beat the hair test, so it's all hearsay and guessing at this point.
Swimming and washing your hair removes toxins, and Keith Thrash recommends doing both as much as possible. Fortunately, the hair test cannot be used alone as evidence because there are no forensic standards. It can only be used when substantiated by other evidence. Also, there are no intoxication standards. I believe if you tested positive for the hair test that you would probably have a good chance of fighting it. It takes several months of pre-cleansing to beat the tests given by Psychemedics.
2.5 High Performance Liquid Chromatography (HPLC)
High performance liquid chromatography (HPLC) is similar to GC, except a liquid carries the sample through the chromotographic columns and the columns are not placed in a heated compartment. HPLC is both sensitive and specific, and it is simpler and faster than GC. Gas chromatography and HPLC are reliable methods for screening, and they allow for simultaneous determination of a wide variety of different compounds. HPLC is used to screen for urinary caffeine levels and has been used to confirm the positive results obtained from other screening techniques. Some steroids can be analyzed with this technique, whereas HPLC and GC lack appropriate sensitivity to detect beta-adrenergic blockers.
An immunoassay is a biochemical test that measures the level of a substance in a biological liquid, typically serum or urine, using the reaction of an antibody or antibodies to its antigen. The assay takes advantage of the specific binding of an antibody to its antigen. Monoclonal antibodies are often used as they only usually bind to one site of a particular molecule, and therefore provide a more specific and accurate test, which is less easily confused by the presence of other molecules. The antibodies picked must have a high affinity for the antigen. If there is antigen available, a very high proportion of it must bind to the antibody.
Both the presence of antigen or antibodies can be measured. For instance, when detecting infection the presence of antibody against the pathogen is measured. For measuring hormones such as insulin, the insulin acts as the antigen.
For numerical results, the response of the fluid being measured must be compared to standards of a known concentration. This is usually done though the plotting of a standard curve on a graph, the position of the curve at response of the unknown is then examined, and so the quantity of the unknown found.
Detecting the quantity of antibody or antigen can be achieved by a variety of methods. One of the most common is to label either the antigen or antibody. The label may consist of an enzyme, radioisotopes such as I-125 Radioimmunoassay (RIA) or fluorescence. Other techniques include agglutination, nephelometry, turbidimetry and Western Blot.
2.6.1 Radioimmunoassay (RIA)
Radioimmunoassay (RIA) is a scientific method used to test antigens (for example, hormone levels in the blood) without the need to use a bioassay. It involves mixing known quantities of radioactive antigen (frequently labeled with gamma-radioactive isotopes of iodine attached to tyrosine) with antibody to that antigen, then adding unlabeled or "cold" antigen and measuring the amount of labeled antigen displaced.
Initially, the radioactive antigen is bound to the antibodies. When "cold" (unlabeled, quest) antigen is added, the two compete for antibody binding sites—at higher concentrations of "cold" antigen, more of it binds to the antibody, displacing the radioactive variant. The bound antigens are separated from the unbound ones. One method of separation used initially was the use of a second antibody directed against the first for precipitation and centrifugation. The use of charcoal suspension for precipitation was extended but replaced later by Drs. Werner and Acebedo, at Columbia University for RIA of T3 and T4 (JCEM 1974). An ultramicro RIA for human TSH was published in BBRC (1975) by Drs. Acebedo, Hayek et al. The free hormone stays in the supernatant, the radioactivity of which is measured and a binding curve is plotted. We prefer to measure the radioactivity of the precipitated hormone.
The technique is both extremely sensitive and specific, but it requires special precautions (because radioactive substances are used), sophisticated apparatus, and is expensive. The technique has been largely replaced by the ELISA method where instead of a radioactive signal, the antigen-antibody reaction is measured by colorometric signals.
The RIA was developed by Rosalyn Yalow and Solomon Aaron Berson in the 1950s. Rosalyn Sussman Yalow received the 1977 Nobel Prize in Medicine for the development of the RIA for insulin. The precise measurement of minute amounts of such a hormone was a key event in endocrinology. This discovery opened the door for the development of the ELISA test.
2.6.2 Enzyme Multiplied Immunoassay Technique (EMIT)
The Enzyme Multiplied Immunoassay Technique, or EMIT, is a common method for screening urine and blood for drugs, whether legal or illicit.
The technique is relatively nonspecific compared to some other analysis methods, such as mass spectrometry, but has the advantage of being fast and inexpensive. It has, however, been shown in some cases to be somewhat inaccurate in its findings.
The EMIT is the cheapest and easiest to perform, and also the most common. However, it is the easiest to fail. If you are well informed, this test is quite easy to pass. Most pre-employment screens will give you the EMIT first, though some businesses will surprise you with a GC-MS test.
Unfortunately, there is no standard procedure to expect. One who has read this file and is well informed may still fail because of the random nature of drug testing labs. If you don't know which urinalysis will be administered, focus on beating the EMIT. If you pass the EMIT, you're off the hook. If you fail the EMIT, they'll give you the confirmation GC-MS test, which is extremely sensitive. Lewis Maltby, director of the Workplace Rights Office, said the EMIT test is wrong 25 to 30 percent of the time.
2.6.3 Fluorescence Polarization Immunoassay (FPIA)
There is little to no information on FPIA, but the basic process works like this. A fluorescein-labelled drug competes with an unlabelled drug for an antibody. The sample is excited with plane polarized light of 490 nm. Fluorescein emits a plane polarized light of 520 nm. Small, free drug-fluorescein, starts rotating faster, leading to less emission. Larger, antibody-drug-fluorescein rotates slower, and produces more emission. The drug sample competes for the antibody with the fluorescein bound drug. The more drug present in the sample, the less fluorescein labelled drug will bind to the antibody, resulting in a lower emission of plane ploarized light. The higher the drug concentration will result in lower light emission values.
FPIA is available for a variety of drugs, and it has a rapid turnaround time, sensitivity, and is easy to operate.
2.6.4 Comparing Analytical Methods
|Scale 1 to 5, with 1 being the best|
2.7 Thin Layer Chromatography (TLC)
Thin layer chromatography (TLC) is a widely-used chromatography technique used to separate chemical compounds. It involves a stationary phase consisting of a thin layer of adsorbent material, usually silica gel, alumina, or cellulose immobilised onto a flat, inert carrier sheet. A liquid phase consisting of the solution to be separated dissolved in a solvent is drawn through the plate via capillary action, separating the experimental solution. It can be used to determine the pigments a plant contains, to detect pesticides or insecticides in food, in forensics to analyze the dye composition of fibers, or to identify compounds present in a given substance, among other uses.
Accuracy is very poor, and this test is rarely used. A TLC kit called TOXI-LAB® by Varian, Inc. is available. This kit has been abandoned for the most part, since EMIT has been improved. Fortunately, it's not used for confirmation anymore.