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What is the difference between a urine drug test and an oral fluid (saliva) drug test?

As an accredited drug testing laboratory, with many years’ experience providing drug testing solutions for businesses, we are often asked which drug tests offer the best insight into an individual’s drug use.  

Although urine drug tests are more commonly used in workplaces that implement random, for cause, post-incident/accident, and pre-employment drug testing, oral fluid (saliva) drug tests are an increasingly popular choice for employers carrying out workplace drug tests.  

In this article, we look at urine and oral fluid (saliva) drug tests, what each test involves, how samples are collected, and what the results of each test can tell us about a person’s drug use. 

Table of contents
  • How can drugs be detected in urine and oral fluid (saliva)?
  • When are oral fluid and/or urine drug tests performed?
  • What is the difference between a urine drug test and an oral fluid (saliva) drug test?
  • How is a urine drug test performed?
  • How is an oral fluid (saliva) drug test performed?
  • How long does it take for drugs to be detected in urine and saliva?
  • How long does it take to get the results of a urine drug test?
  • How long does it take to get the results of an oral fluid (saliva) drug test?
  • How accurate are oral fluid (saliva) and urine drug tests?
  • Which drug test is better – urine or oral fluid (saliva)?
  • Where can I get a urine or oral fluid drug test?

How can drugs be detected in urine and oral fluid (saliva)?

When a person consumes drugs, they are broken down by the liver, and a proportion of the drug and its metabolites are released into the bloodstream.

A small, self-contained screening device such as a urine sample pot or an oral fluid device can then be used to detect these substances in a person’s urine or saliva.

Unlike other forms of testing such as hair drug testing and nail drug testing, urine drug tests and oral fluid/saliva drug tests provide what is known as a ‘narrow-window’ of detection.

This means both tests can detect substances for a short period of time (a few days) from when the person initially consumed drugs.

When drug testing is performed in the workplace, any non-negative samples (indicating the presence of certain substances) are returned to the laboratory for in-depth analysis and confirmation of the substances that were initially detected when the donor provided their sample.

When are oral fluid and/or urine drug tests performed?

Workplace drug testing is performed for a variety of reasons and is especially important in safety critical industries such as construction, manufacturing, rail, engineering, aviation and more, where the use of drugs can increase the risk of incidents or accidents and put people at risk.

However, it’s important to remember that drug use is a widespread societal concern, meaning that it doesn’t only affect industries where health and safety is regarded as a higher priority.

Drug use affects businesses of all sizes, across every sector.

According to the Crime Survey for England and Wales (year ending March 2020), as many as 1 in 11 adults aged 16 to 59 consumed drugs in the previous 12 months. This equates to 9.4% of adults (approximately 3.2 million people).

Under the Health and Safety at Work Act 1974, every business has a duty of care to ensure as far as is reasonably practicable, the health, safety, and welfare of employees at work.

Some circumstances where an employer might consider carrying out urine drug tests or oral fluid/saliva drug tests include:

  • Random drug testing – also known as ‘unannounced’ drug testing, this type of testing helps ensure employees are working in a safe environment, by selecting random employees for drug testing at intermittent intervals throughout the year.

    Many studies show that random testing is effective in reducing accidents/incidents and absenteeism. It also helps foster a culture of health and safety, where all employees feel responsible for maintaining a safe workplace.

  • For Cause drug testing – sometimes referred to as ‘with cause’ or ‘reasonable suspicion’ drug testing, this type of testing is performed where an employer has grounds to suspect that an employee is misusing drugs in the workplace.

    It may be that an individual is displaying signs of possible drug misuse such as unusual behaviour, reduced productivity, or unexplained absence.

  • Post-incident/accident drug testing – this type of testing is performed where drug use is suspected as a contributing factor in a workplace accident.

  • Pre-employment/pre-appointment drug testing – these tests are performed prior to a new employee joining a business and are becoming increasingly common as part of the recruitment process.

    In addition to urine and oral fluid drug tests, which provide a ‘narrow window’ of detection for drug use, nail clipping and/or hair strand drug testing is also sometimes used for pre-employment screenings.

    Both nail drug testing and hair drug testing provide a ‘wide window’ of detection for drug use (up to 12 months for head hair and up to 12 months for nails).

  • Post-rehab/Return-to-work drug testing – also known as ‘abstinence’ or ‘follow-up’ drug testing, these tests are performed after an employee has previously received a confirmed positive drug test result and can facilitate an employee’s return to the workplace following previous drug misuse.

What is the difference between a urine drug test and an oral fluid (saliva) drug test?

Both urine drug tests and oral fluid (saliva) drug tests provide a quick, simple, and non-invasive way to find out whether a person has recently consumed drugs.

However, there are a couple of fundamental differences between the two tests.

The most obvious being the type of sample used to test for the presence of drugs, with a urine drug test requiring a urine sample, and an oral fluid drug test requiring a sample of the individual’s saliva.

The other key difference is the detection window for each test i.e. the period of time during which drugs can be detected in a urine or saliva sample. See How long does it take for drugs to be detected in urine and oral fluid?

However, the procedure surrounding the sample collection process is the same for each test.

This means that samples collected during workplace urine and oral fluid/saliva drug tests are always collected under strict chain of custody conditions.

This reduces the likelihood of samples being tampered with, ensures samples are collected from the right people, and means that the test results are admissible should an employee dispute the results.

All non-negative test samples for workplace drug tests are also subject to stringent analysis in the toxicology laboratory, to provide final confirmation of the results.

How is a urine drug test performed?

During a urine drug test, the donor will be asked to provide a urine sample using a fully self-contained urine screening kit that can detect the presence of certain drugs in a donor’s urine sample.

Prior to sample collection, the trained sample collector will prepare a suitable toilet for the donor to use while collecting their sample, taking careful measures to prepare the area, the toilet, and the washing facilities to reduce the possibility of the sample being tampered with.

The donor will then collect their urine sample in private.

Once testing is completed, the sample collector will look at the test strips on the side of the pot to assess whether any substances were detected or not.

For a negative result, coloured lines will appear on the test strips indicating that none of the substances were detected in the sample.

For a non-negative result, no coloured lines will appear on the test strips for the corresponding drug. This indicates that the substance has been detected.

The urine sample will then be returned to AlphaBiolabs’ state-of-the-art toxicology laboratory so that a more in-depth analysis can be performed, and the result can be confirmed.

How is an oral fluid (saliva) drug test performed?

An oral fluid or saliva drug test is performed by using a self-contained oral fluid device to take a sample of a person’s saliva.

The device will usually be equipped with an absorbent sample collector that the sample donor rubs around the inside of their mouth to collect saliva for testing, and a test cassette for analysis (depending on the device that is being used for the test).

Once the donor has collected their sample, the absorbent collector is inserted into the test cassette.

For a negative result, a line will appear next to each of the substance classes on the device, indicating that no substances were detected in the sample.

For a non-negative result, a line will fail to appear next to one or more of the substance classes on the device. This indicates that the corresponding substance was detected in the saliva sample.

If the test returns a non-negative result, two further saliva samples are collected and returned to AlphaBiolabs’ accredited toxicology laboratory for in-depth analysis, so that the result can be confirmed.

How long does it take for drugs to be detected in urine and saliva?

Urine drug tests and oral fluid/saliva drug tests provide a narrow window of detection.

This means that each test can only tell us whether an individual has been using drugs in the few days prior to the samples being collected.

A urine drug test provides a window of detection of up to four days.

An oral fluid (saliva) drug test provides a window of detection up to 48 hours.

This narrow detection window means that, where an employee is suspected of being under the influence of drugs, or where an incident or accident has occurred and drug use is suspected, it is crucial that these tests are performed quickly to provide the best chance of substances being detected.

For businesses that require an historic overview of an employee’s drug use, such as those implementing pre-employment or pre-appointment testing, nail drug testing or hair drug testing can provide a ‘wide window’ of detection (up to 12 months for head hair and up to 12 months for nails).

How long does it take to get the results of a urine drug test?

An AlphaBiolabs urine drug test provides results in minutes, using a self-contained screening unit that can detect up to 14 different drugs.

The drug screening kit has test strips built-in to reduce urine handling.

The presence of two magenta-coloured lines indicates a negative result for the corresponding drug.

Where no lines appear at the Test line, and only the magenta-coloured band appears at the Control line, this indicates a reaction for the corresponding drug (a non-negative result).

For a non-negative result, the trained sample collector will transfer the urine sample in equal quantities into two separate containers, representing an A sample and a B sample. Each container is then sealed with tamper tape to ensure chain of custody is maintained.

Both urine samples (A and B) are then safely transported back to the laboratory for in-depth analysis, and confirmation of the results.

AlphaBiolabs is proud to offer the fastest laboratory confirmations in the industry, with same-day results available for workplace drug tests if required.

How long does it take to get the results of an oral fluid (saliva) drug test?

An AlphaBiolabs oral fluid (saliva) drug test provides results in minutes, using a self-contained screening unit that can detect a variety of drugs and their metabolites.

Typically, the oral fluid device consists of two components: an absorbent sample collector for obtaining a saliva sample, and a test cassette for the analysis (depending on the device being used).

The test cassette includes a detection window with two test strips, which displays the Control and Test lines.

Once the donor has collected their sample using the absorbent collector, it is then inserted back into the test cassette for analysis.

If the test result is negative, a line will appear alongside the respective substance class (drug). This means that none of the substance was detected in the sample.

If no line appears next to the substance class, this means that the substance was detected in the sample, indicating a non-negative result.

For a non-negative test result, a further two oral fluid/saliva samples must be collected for laboratory testing. Both samples are then returned to the toxicology laboratory for in-depth analysis and confirmation of the test result.

AlphaBiolabs provides the fastest laboratory confirmations in the industry, with same-day results available for workplace drug tests if required.

How accurate are oral fluid (saliva) and urine drug tests?

Both urine drug tests and oral fluid (saliva) drug tests are extremely accurate and reliable, based on the sample provided by the donor at the time of collection.

Our workplace sample collectors follow strict procedures throughout the collection process to ensure that chain of custody is maintained.

This includes asking a workplace representative (usually a manager) to confirm the identity of the sample donor, or viewing their work ID badge which has a photograph of the sample donor printed on it.

Tamper tape is also used to secure non-negative samples before they are returned to the laboratory for confirmation testing.

The addition of this laboratory confirmation provides further reassurance that all drug tests results are 100% reliable, and that the findings are accurate. Furthermore, detailed laboratory analysis removes any doubt whatsoever about which substances were detected.

Each of these steps helps ensure that our workplace drug test results are defensible, whichever method of testing you choose.

This is especially important should the person being tested (the employee) decide to contest the results of the drug test for any reason.

AlphaBiolabs can also train representatives from your own staff to perform workplace drug testing and sample collection to the highest standards, while following chain of custody procedures.

Which drug test is better – urine or oral fluid (saliva)?

Thanks to advances in modern toxicology testing, both urine drug tests and oral fluid/saliva drug tests are extremely accurate and reliable, based on the sample provided at the time of collection.

The self-contained testing kits used for urine and oral fluid (saliva) screening are highly sensitive, detecting trace amounts of substances in the donor’s sample.

Employers who are considering introducing workplace drug testing, or updating their existing substance misuse policy, should consider the benefits of the tests and how each test might suit the needs of their business.

For example, oral fluid/saliva drug testing can be useful if you do not have anywhere suitably private for the donor to collect a urine sample, or if a urine sample cannot be provided for another reason.

Oral fluid drug testing has become increasingly popular among employers looking for a discreet, non-invasive way to carry out drug testing. Some employees may also feel more comfortable providing a saliva sample, than they would providing a urine sample for testing.

However, an oral fluid/saliva drug test can only provide a window of detection of up to 48 hours after drugs have been consumed.

Urine drug testing is a highly accurate and well-established method of testing for drug use in the workplace, providing a wider window of detection than oral fluid drug tests (up to four days).

Both urine drug tests and oral fluid drug tests can be used for a variety of reasons including random, for cause, post-incident/accident, and pre-employment/pre-appointment testing, as well as post rehab and return to work testing.

Where can I get a urine or oral fluid drug test?

AlphaBiolabs offers bespoke workplace drug testing for business of all sizes across a range of sectors, including urine drug tests and oral fluid (saliva) drug tests.

We have extensive experience working with senior managers, HR professionals, and occupational safety & health professionals, who are looking to introduce drug testing for the workplace or want to update their existing substance misuse policy to include urine and/or oral fluid (saliva) drug testing.

To find out more about workplace drug testing or for confidential advice on which tests are best for your business, call our workplace team on 0333 600 1300 (select option 2) or email workplace@alphabiolabs.com, and a member of the team will be in touch to discuss your bespoke package.

Last reviewed: 21/06/2022
Barbara Wainwright, AlphaBiolabs

Barbara Wainwright

Workplace Company Trainer at AlphaBiolabs

A 30-year veteran of Greater Manchester Police, Barbara joined AlphaBiolabs in 2020 as Workplace Company Trainer.

Barbara’s main responsibilities include delivering sample collections training to AlphaBiolabs’ UK network of clinicians and providing sample collection training for businesses within AlphaBiolabs’ expanding portfolio of workplace customers.

Barbara also delivers Management Awareness Training; helping employers recognise the signs of drug and alcohol misuse in the workplace. This is essential for industries with safety-critical roles such as manufacturing, engineering, and logistics.