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drug screening matrix

Urine versus Oral Fluid Drug Screening I Which matrix to use?

Which matrix to use for drug testing?

This increase in drug prevention programs has boosted the development of numerous portable drug-testing devices designed for use in the field, which vary not only in applicability and quality but also in the matrix used for testing.

Every matrix meets particular needs. While oral fluid can detect recent drug use, the urine matrix can detect distant drug use as the window of detection of drugs/metabolites can go up to several days.

The ease of collection and relatively high concentrations of drugs in urine make urinalysis a cost-effective solution as it does not require expensive instrumentation for drug detection and quantification.

In fact, urine has long been the most widely used matrix for on-site drug screening because it has a longer detection window, is non-invasive and cost-effective. However, the urine matrix has certain limitations that oral fluid can make up for (sample adulteration, invasion of privacy, etc.).

Besides being non-invasive, oral fluid samples are also easier to collect than urine. The scientific community has recognized oral fluid as a reliable and highly effective matrix that can detect the recent use of illegal drugs or prescription drugs.

Drug testing steps

The typical drug testing is usually done in two steps:

  1. Initial testing: it is used to identify the presence of the targeted drug(s)
  2. Confirmation testing: it determines the type and quantity of drug or drug metabolite present in the sample

First, you perform an on-site drug screening. Second, if the test suggests that drugs may be present, you send the sample to a laboratory for confirmation testing. It is very important to send the sample to the laboratory to confirm a positive result because certain foods, beverages, adulterants or medicines can affect the results of an initial test. Laboratory tests (using more sensitive methods) are the most reliable way to confirm drugs of abuse.

Initial drug testing can be performed by:

  1. Point-of-care (POC) tests
  2. Laboratory-based tests

In this article, we will focus on point-of-care drug testing, also known as instant drug testing or rapid drug testing. Point-of-care testing includes any tests that are performed at or near a patient and at the site where the sample is collected. Point-of-care drug tests generally use urine or oral fluid (saliva) for the test matrix (specimen). Results are typically available relatively quickly so that they can be acted upon without delay.

Point-of-care drug testing

Instant drug testing usually screens for drugs such as marijuana, opioids, amphetamines, barbiturates, benzodiazepines, cocaine and phencyclidine (PCP).

The sample matrix and the cut-off level of a point-of-care drug test must be carefully selected according to the regulatory requirements and the desired detection windows. Oral fluid offers narrow detection windows, while urine proposes wide-window drug testing.

What does cut-off level refer to?

In drug testing, the cut-off level represents the concentration above which an individual is considered to be positive for presumably taking drugs. It is usually measured in nanograms per millilitre (ng/ml).

A good understanding of urine and oral fluid matrices allows you to choose the optimal solution for your particular needs. Here are the pros and cons of oral and urine matrices.

Oral fluid matrix

The oral fluid matrix is widely regarded as the second most reliable sample type for detecting recent drug use after blood. Unlike blood, the oral fluid sample collection is non-invasive.

Oral fluid is now gaining ground due to technological advancements. Recent advances in technology and the introduction of commercial oral fluid assays have indeed established oral fluid as a viable alternative matrix (sample) to urinalysis for drug testing on roadsides, in workplaces, rehabs, etc.

Definition of Oral Fluid

Oral fluid is a mixture of saliva from three different glands, microflora (e.g. oral bacteria, viruses, etc.), blood and blood derivates (e.g. gingival crevicular fluid, etc.), food debris and toothpaste/mouth-wash components.

What are the pros of Oral Fluid?

The advantages of using oral fluid specimens over urine are:

  1. A non-invasive collection method with no invasion of privacy
  2. High integrity of the samples

Oral fluid samples are collected non-invasively, with relatively no invasion of privacy and under supervision. This removes the need for collection facilities with professional personal or for washroom facilities, the need for a same-sex observer for collection and the problem with shy bladder syndrome of the person proving the sample. The collection process is, thus, faster and easier than for urine. Furthermore, there is minimal risk for adulteration (contamination), thus saving time and resources. All of these makes oral fluid (saliva) ideal for on-site drug testing.

Attention has to be paid before buying an oral fluid drug test kit as the sample collection procedure has a significant effect on the drug concentration.

Why choose oral fluid drug testing?

Oral fluid testing for safety-sensitive positions

Employers tend to prefer oral fluid tests to detect recent drug use among their employees in order to keep their workplace safe and secure. Moreover, the oral fluid sample collection is directly observed. There is then no place for sample adulteration.

Oral fluid testing for roadside impaired driving

Oral fluid samples can also be collected at the roadside, close to the time of a suspected impaired driving offence. Let's remind you that the oral fluid matrix is mostly screened for parent drugs (the administrated drug). Parent drugs generally don't stay in the body for a long time, unlike drug metabolites. Therefore, their detection is a reliable indicator that a person used the drug recently.

Moreover, unlike urine drug testing, the oral fluid collection process does not require any facilities or same-sex observers making drug testing process easier for police officers.

What about the cons of Oral Fluid?

Drug Testing Interpretation

Limitations of oral fluid as a sample matrix include the fact that drug concentrations cannot be related to an exact degree of impairment in the driver, nor can they be used to predict drug concentrations in the blood (practical works show great variability). It is also worth noting that not all governments and private agencies recognise oral fluid test results for mandatory drug testing (e.g. DOT compliance rules).

Oral Fluid Specimen Collection

Food and Drinks consumption

Food and drinks can interfere with oral fluid samples and cause false-negative or false-positive results. The donor is usually required to refrain from eating or drinking for at least 10 minutes before drug testing.
Dry mouth syndrome (xerostomia)

Drugs, whether taken by mouth or injected, come with a risk of side effects such as dry mouth syndrome. An example of a drug that most commonly causes dry mouth is cocaine.

Urine matrix

Urine is recognised as the primary matrix for drug testing. Urine drug tests, also known as urine drug screens or UDS, are a common way to monitor and detect a person's use of illegal drugs or prescription drugs.

What are the pros of the Urine matrix?

The advantages of using urine samples over oral fluid (saliva) are:

  1. More defensible in a court of law
  2. Longer windows of detection for distant drug detection

Urine, or urinalysis, is the most widely used specimen and is the required matrix for industries like the DOT and federal drug testing. Moreover, results from urine testing are more likely to stand up in court. The reasons are it can detect most drugs, the urine matrix is effective in detecting recent drug use ( usually one to three days) and enables convenient and non-invasive sampling.

Why choose urine drug testing?

Drug testing in the military

Veteran matrix to test for drugs of abuse and prescription drugs in urine. In fact, all military branches have adopted a “zero-tolerance” approach to drug use. Therefore, the military uses urinalysis to monitor and discourage its members from using illicit drugs and controlled substances. The choice of urine matrix can be explained by the need for a complete and larger overview of the members' drug use.

Urine drug testing for high-risk professions

Besides offering a longer window of detection for drugs of abuse and prescription drugs, urinalysis testing is also approved for federal testing in the United States. Urine drug tests are therefore conducted by the military to monitor and deter its members from using illicit drugs as discussed earlier.

What about the cons of Urine?

One of the downsides to urine is the risk associated with drug “cheaters” or urine sample adulteration. Moreover, the urine sample collection process requires the need for collection facilities or same-sex observation in order to preserve the donor’s privacy.

Sample collection procedure

The collection procedure must be very specific in order to minimize the possibility of procedural errors and to prevent adulteration. Although no certification or medical education is usually required for the collector, a training course is necessary. The collector is a trained individual who instructs and assists the donor at a collection facility, who receives and makes an initial inspection of the sample provided by the donor. The collection procedure can take more time in the case of drug testing with urine than with oral fluid.

Drug Detection Windows

Drugs and metabolites (by-products of the parent drug) can generally be detected from a few minutes up to a few days. Nevertheless, this depends on the particular substance taken, the person being drug tested, drug use frequency, the matrix used and the chosen cut-off levels.

Cut-off levels and Detection Windows

While buying a drug test, you must pay attention to the chosen cut-off levels. Indeed, lower cut-offs are observed to give longer detection windows.

Oral Fluid gives short detection window

By using oral fluid, you can have a short detection window. Depending on the substance used, the prevalence of use and route of administration, a drug may be detected in oral fluid in less than one hour and up to 48 hours.

The oral fluid matrix provides a “narrow detection window', hence recent drug use detection. If you are looking for longer detection times, you better use urine samples.

Urinalysis gives long detection window

Although urine samples are unable to detect very recent drug usage, they offer a longer detection window. Urine drug testing is particularly useful to gain a more comprehensive overview of a person's drug use. Urinalysis is known as a 'wide window' form of drug testing. In fact, a urine drug test can detect the drug over a longer period than an oral fluid drug test. When a person uses a drug very frequently or intensively, the drug detection time can go up to 30 days. The testing time range is therefore longer.

⚠ However, let's remember every drug and individual is different. Therefore, detection times can range depending on the type of drug, the donor, frequency of use, and other factors.

What does a drug test screen for?

A drug test can detect the presence of either the parent drug (administrated drug) or the metabolite (a by-product of the parent drug) depending on the matrix used. For the oral fluid matrix, the tests mostly screen for parent drugs. Parent drugs generally stay in the body less long than drug metabolites.

Oral Fluid detects Parent Drugs

The proportion of parent drugs and metabolites is different in each matrix. Generally, oral fluid has a higher proportion of parent drugs, with metabolites in lower concentrations as its detection window is “narrow”.

Urine detects Metabolites

Urine generally screens for metabolites that the body produces after drugs are metabolized. In general, drug metabolites are less active and less toxic than the parent drugs. The by-products remain in the body much longer than the drug itself (parent drug).

What is important to remember is that some metabolites remain in the body much longer than the parent drug. Thus, metabolites usually have a longer window of detection than their parent drugs.

Here's an example of cocaine screening. One of cocaine's metabolites, known as benzoylecgonine, stays in the donor's system significantly longer than cocaine (the “parent” or administrated drug). In this case, a drug test has a higher probability of identifying a cocaine user by looking for the presence of the metabolite benzoylecgonine, rather than the parent drug cocaine.

However, the detection of metabolites or their parent drugs does not mean that the donor is under the effect of the drug detected. 

What matrix to choose?

There is no matrix better than the other. However, there is only one that will best meet your needs. Synens created a free white paper to help you choose the right matrix and learn more about Drug Detection Window. So, before choosing your matrix for drug testing, you should think about your particular needs. What do you want to screen for or how far do you need to detect substances?

Drug Testing to address the global problem of Drug Addiction

Over 35 million people suffer from drug use disorders, according to the UNODC World Drug Report 2020. The growing and evolving problems of drug abuse require new and innovative drug testing strategies to reliably and reproducibly detect signs of abuse. This global issue has led to an increase in drug prevention programs.

Drug Policies

In the United States, opioid awareness programs are being created in schools. The purpose of those programs is to educate students of all ages about the opioid and substance abuse crisis. Europe has also a drug problem and knows it. But the Europeans' approach to it is quite different from the American “war on drugs. Besides having some of Europe’s strictest drug laws, France has recently started a war on drugs. The Head of State, Emmanuel Macron, intends to tackle drug crime problems, announcing millions in new financing and a new policy to target drug traffickers with “harassment” in the city’s poorest and most vulnerable areas.

What solution does Synens provide?

At Synens, we offer preventive drug testing solutions using oral fluid for recent drug use detection. Synens oral fluid drug test kit, OM90, has an integrated sample collection system which makes the whole process even faster and easier. After collecting the specimen, you do not need any additional steps for the analysis of the sample. It is done directly by test. Synens OM90 oral fluid drug test kit can screen for up to 9 drugs in one single test. If you have any questions regarding Synens drug testing solutions, you can directly ask our team. You just need to click right here!

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