Frequently Asked Questions
General Testing
Urine Testing
Oral Fluid Testing
Hair Testing
Lab Testing
Principles of Testing
There are times when we prefer to use the term “substance” instead of “drug”. The term substance abuse therefore covers not only the misuse of illegal drugs but also of alcohol, solvent, tobacco, medication and prescription drug misuse.
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In order to feel an effect, active substance(s) from the compound being taken must enter the blood stream so that it can be transported throughout the body, eventually reaching the area where it is active. This can be achieved through a variety of methods, such as eating (ingesting), inhaling (smoking), insufflation (snorting), or injecting.
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The liver is responsible for the metabolism of many foreign substances. Given that all blood in the body will pass through the liver at some stage, once a drug is in the bloodstream it will start being broken down (into drug-metabolites) and the reduced level of the active substance in the body will result in it’s effects diminishing over time.
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Drugs and their metabolites find their way from the blood to all other body fluids: urine, oral fluid, sweat, and tears. During hair formation, molecules from drugs can become trapped between the proteins that form the hair. The method employed for drug detection is highly dependant on the situation, but the most common tests involve taking urine and oral fluid samples because they are the most reliable.
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Testing is carried out for a variety of reasons such as demonstrating abstinence, maintaining rehabilitation programmes, identifying substance abusers, and monitoring high-risk staff.
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General Testing
A POC test stands for Point Of Care test, that is a test which can be performed on-site with immediate results available.
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A screening test (usually a POC test) is designed to be qualitative – that is the result is given as positive or negative. A confirmation test (lab test) is usually performed using the GC/MS or LC/MS techniques (see below). These techniques allow each type of molecule to be uniquely identified quantitatively, thus differentiating between different types of substance within each drug class, for example opiates can be differentiated into morphine, codeine, heroin, etc.
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No. Despite the fact that these medications are related to opiates, they are different enough that they do not interfere with the OPI test.
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What are the advantages and disadvantages of testing using the three most common methods: urine, oral fluid, and hair?
Deciding upon which test method to use is dependent on what the purpose of the testing is.
Oral Fluid
For the majority of illicit drugs, once the active substance enters the blood stream it will be only minutes until it is detectable in oral fluid. However, after anywhere from 12 hours to 3 days it will become untraceable in oral fluid. Therefore, oral fluid is a good medium to choose for drug testing where it is important to know if someone has recently taken something and is possible still under the influence of its effects.
Urine
It can take up to 6 hours before any substance becomes detectable in the urine. The length of time that any particular substance can be detected using urine is dependent on several factors: frequency of use before the test, quantity and quality of the drug, and lifestyle and metabolism of the person. However, most illicit drugs can be detected for a few days in urine if consumed only once. For someone regularly using, the time of detection can increase to several days or even weeks, depending on the drug.
Hair
Because a hair has to grow from under the skin, it takes days before any substances find their way in a hair outside of the body. Once trapped it stays in the hair and can be detected for months. Therefore, hair testing is very useful for looking at someone’s drug use in the recent past because if someone knows they will be tested they can simply abstain from taking for a couple of weeks in order to pass a test using oral fluid or urine.
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The cut-off level of a test is the level at which a negative result becomes positive. The cut-off level is measured as a concentration (ng/mL). If the concentration of a drug in the sample is higher than the cut-off level, a positive result is returned (absence of line at the test line area). If it is below the cut-off level a negative result is returned (any indication/presence of a line at the test area). Cut-off levels should not be taken to represent an "impairment threshold", their purpose is to make sure that any positive test is the result of active drug taking by the donor rather than through accidental exposure. The cut-off levels of our tests are in accordance with the international standards set by SAMHSA.
Note: It is not advisable to confirm a POC test with a laboratory screening test as compounds screened for and cut-off levels may vary.
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Effectively there is no difference. Subutex is the trade name under which Buprenorphine is sold in the UK.
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Poppy seeds contain traces of opium, and therefore eating a very large amount can cause a positive result on opiate tests. This is not a true false positive, as the donor is effectively testing truly positive for opiates, however it is often referred to as a false positive because the donor has not taken any drug for recreational purposes.
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No. This is often used as a reason why someone has returned a positive THC result, but it would take very exceptional circumstances for this to occur.
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Tetra-hydro-cannibinol (THC) is one of the few substances of abuse that dissolves in fats/oils much better than it does in water. The fat cells in the human body absorb the THC molecules and these are re-released by the fat cells over time (days to weeks).
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There are several opiate-based medications that trigger a positive result for the opiate test. Any donor taking medication containing codein (Nurofen Plus), dihydrocodeine, and co-codamol should be expected to return a positive result for opiates.
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No. Whether the sample was urine, oral fluid, blood or hair, there is no way of knowing when it was taken or the quantity and quality.
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Any evidence of a line on any POC test is classed as a negative result (the only exception is for pregnancy tests where a line indicates a positive result). There are many factors which affect line intensity, therefore you should never use the line intensity as a guide to how much substance has been taken.
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These abbreviations stand for Gas Chromatography/Mass Spectrometry or Liquid Chromatography/Mass Spectrometry, respectively. These techniques are considered the most sensitive and accurate for the detection of substances. See below for a more complete explanation. LC/MS is the preferred method for oral fluid laboratory testing.
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This measurement stands for nano-grams (of substance) per milli-Litre of volume (urine, oral fluid, blood, etc.) and is the unit generally used to describe the amount of substance in a sample. One nanogram is 0.000000001 of a gram, while a millilitre is one-thousandth of a litre; this is the equivalent to 1 gram in 1 million litres of water (an Olympic swimming pool contains 2.5 million litres of water).
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There are two different cut-off levels for opiate tests, and each cut-off has two abbreviations. MOP/OPI 300 (Morphine) tests for opiates at a cut-off level of 300 ng/mL, while OPI/OPI 2000 signifies that the cut-off level is 2000 ng/mL. All of these test for exactly the same substances.
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No. There are two different cut-off levels when testing for opiates (see question above). In our experience, if someone is offering you a POC heroin test it is probably just an OPI 2000 test.
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Urine Testing
The most common form of adulteration is the use of water to dilute the sample. This can be achieved by drinking a lot of water hours before being tested, or diluting the urine sample with water after it has been collected. Bleach, in addition to a variety of commercial adulterants, is also used sometimes to try and mask the presence of drugs.
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The abbreviation SVT stands for Sample Validation Test. This test is used in conjunction with a urine test in order to check if the urine sample has been in any way adulterated, checking the creatinine level, specific gravity, and pH of the urine sample.
Oxidants: Oxidising agents such as bleach and hydrogen peroxide are commonly used adulterantants that can mask the presence of some drugs. Normal human urine should not contain oxidants.
Specific gravity: This parameter effectively measures how concentrated the urine sample is, as a higher or lower amount of minerals and salts contained in urine will increase or decrease the specific gravity, respectively. Urine always has a higher specific gravity than water, so any addition of water to a urine sample will reduce the specific gravity and be detectable with an SVT.
pH: This is a measure of a liquids acidity or alkalinity. If a urine sample is adulterated to be highly acidic or alkaline, the chemistry of the test can be affected so that even drug containing urine returns a negative result.
Temperature: A fresh urine sample will generally be between 32oC and 36oC. If your test has a temperature strip this can be measured immediately, if not a thermometer is necessary. If the test has been stored at room temperature (or allowed to warm up to room temperature if stored in a cool place) then any deviation outside of this temperature range should raise suspicion of sample adulteration.
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Oral Fluid Testing
To prevent any food or liquids ingested by the donor from potentially interfering with the test. Ten minutes is the time necessary for the oral fluid in the mouth to complete a full cleansing cycle.
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No. The swabs used with QD tests are all stored in hygienic sealed packaging until use. When used correctly there is no contact between the collector and the donor (and the donor’s oral fluid). The swab is tasteless and vegan/vegetarian-friendly, containing no animal products and no chemicals.
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Hair Testing
The standard hair test covers a time frame of about 90 days. It is possible to go back longer depending on the length of the hair.
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Most drugs of abuse can be detected using hair including: cocaine, marijuana, opiates (heroin, morphine, codeine), methamphetamine, amphetamine, and ecstasy.
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Approximately 50-70 strands of hair that are up to 3.9 cm long are required.
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As blood enters and nourishes the hair follicle during growth, any substances circulating in the bloodstream have a chance of becoming trapped between the proteins of the hair strand and they remain there throughout the growth of the hair.
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Gas chromatography uses a separation technique to divide the urine extracts into the component parts. An inert gas carries the urine through chromatographic columns, and the samples are separated by their boiling temperature and by their affinity for the column. Compounds are identified by separation time, called retention time. The retention time is unique and reproducible for each drug in a given chromatographic column.
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The most precise procedure for detection of banned substances is a combination of GC and MS. Gas chromatography/mass spectrometry is a two-step process, where GC separates the sample into its constituent parts, while MS provides the exact molecular identification of the compounds. Compounds are separated by GC and are then 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 to break up into molecular fragments. The fragmentation pattern is reproducible and characteristic, and is considered the "molecular-fingerprint" of a specific compound.
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The LC/MS/MS method is the prefered method for oral fluid confirmation testing over GC/MS for the following reasons.
- The derivatisation methods necessary to convert a drug into a volatile state necessary for analysis with GC/MS can damage it which could lead to decreases in sensitivity and detectability.
- LC/MS/MS method can pick up a wider range of analytes.
- The tandem mass spectrometry method used with the LC/MS/MS machine provides highly specific identification at a molecular level.
- Confirmations can be supplied much quicker because there is less sample preparation time for LC/MS/MS.
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The spelling of this name was changed from amphetamine to amfetamine in 2003/04 in order to conform with European and international standards.
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