Why Choose Oral Fluid versus Urine Drug Testing?

Oral fluid testing can detect drugs immediately after the most recent use and up to 4 days later. Conventional drug testing with urine is unable to detect usage in the first four hours after use.

The use of oral fluid combined with the high-precision testing instruments used by Forensic Fluids Laboratories offers many benefits over other types of testing methods. When comparing saliva drug tests vs urine drug tests, consider the following advantages and how they will benefit your hospital, clinic, office or lab.

Early Detection Window

Oral fluid testing has the ability to detect drug use within the first few hours.  This is a window of time that is omitted by urine test results. In some cases, it will return a positive result immediately after usage. This, with its ability to detect most drugs from 1 to 4 days after last use, makes it the best testing method for both impairment and post-accident testing. The early detection time is also very useful in dosage monitoring.

Deeper Insight into Drug Levels

For both urine and saliva testing, all samples undergo an immunoassay screening process which results in either a positive or negative result. Merely screening with immunoassay may return false positives as a result of cross-reactions with other substances. Immunoassay screenings do not provide an individual identification of each drug, which is why Forensic Fluids Laboratories uses LC/MS/MS confirmation to ensure that the testing is entirely accurate.

Every sample testing positive during the immunoassay screening process at Forensic Fluids is then confirmed using the most sensitive drug testing method available. Liquid chromatography tandem mass spectrometry (LC/MS/MS) identifies each drug carbon by carbon and hydrogen by hydrogen by its mass.

Faster Turnaround

Forensic Fluids Laboratories leads the industry by reporting negative tests within 8 hours of receiving the sample and positive samples with 24 hours. The simple collection process only takes 1 to 5 minutes before samples can be sent directly to Forensic Fluids. Saliva samples can be collected in nearly any location and under most conditions.  Using the most technologically advanced tools combined with an incredibly simple collection process, turnaround times are the fastest in the industry.

Strong Correlation to Impairment

Compounds that are present in a person’s blood are always present in their saliva. Saliva tests measure the compound of a drug known as the parent compound: the psychoactive element of the drug. Detection of the parent compound in saliva indicates that the drug has entered the blood stream.  Higher levels of the parent compound indicate higher levels of the drug contained within the body. This means that saliva levels can be used to measure impairment.

In contrast, urine tests do not measure the parent compound, they measure the by-product compounds known as "metabolites", which do not correspond with impairment levels.

Greater Integrity of Results

Oral fluid samples are first screened using an enzyme-linked immunoassay technology (ELISA).

Any sample testing positive after screening is tested again using Liquid Chromatography Tandem Mass Spectrometry (LC/MS/MS), the most sophisticated and accurate method available. LC/MS/MS is more accurate and 100 to 1,000 times more precise than Gas Chromatography Mass Spectrometry (GC/MS). Forensic Fluids Laboratories uses the most technologically advanced equipment available. Read more about screening and confirmation.

Eliminate Adulteration

Urine testing is incredibly easy to cheat, beat, or otherwise falsify. Such techniques involve adulterants that interfere with the test results or take advantage of the opportunity  to cheat due to the privacy required when collecting a urine sample which is not the case with oral fluid.

All oral fluid drug tests are administered under supervised observation, making concealed tampering with the test sample virtually impossible. We have tested a wide range of adulterants that are available on the market and have not found any that can interfere with an oral fluid test when properly conducted.

How do you cheat or beat a saliva drug test? The short answer is: you can't; if it is done correctly.

A Better Process for Collection

In minutes, a sample can be collected nearly anywhere. No third-party labs, additional scheduling, or special facilities are needed. Sensitive gender, observation, and privacy issues often associated with urine collection are eliminated for everyone involved. The results are as accurate as a blood test, but without clinics, pain or needles.

Regulatory agencies do not consider oral fluid a bio-hazard and is not subject to the same handling and disposal issues as urine and blood. After the sample is collected, all that's needed is to record the paperwork, package, and send it in the prepaid envelope. It is, by far, the easiest drug test to administer and manage.

Comparative Study - Oral Fluid versus Urine Drug Testing

This comparative study exemplifies the accuracy and dependability of oral fluid drug testing. It is important to note that the oral fluid positive rates are higher in most categories, with significantly more positives in THC, Cocaine, and Amphetamines.

Drug Category Oral Fluid
Jan-Oct 2001
Urine (DOT)
Jan-Dec 2001
THC 3.22% 1.72%
Cocaine 1.12% 0.60%
Opiates 0.23% 0.26%
PCP 0.03% 0.05%
Amphetamines 0.47% 0.29%
Total (%) 5.06% 2.92%

Source: Journal of Analytical Toxicology, Vol. 25, November/December 2002

Saliva THC v Urine THC - How long?

In general, what is in the blood, is in the saliva. If a drug is smoked, like THC, residual THC may appear in the oral cavity for about 3 minutes after ingestion, resulting in higher positive levels. THC psychoactive effects are seen for 3 to 5 hours after normal drug use, although further effects for longer periods have been identified. Delta 9 THC, the parent, and 11-hydroxy-9-delta-9-THC, the metabolite, are the psychoactive compounds.

Saliva THC

Delta 9 THC is the parent compound. When found in saliva, this means possible impairment because the drug has entered the blood stream and affected the brain, thus affecting motor skills. Levels we have measured in saliva in the lab range from 0.5ng/mL and higher (1 ng/mL = 1 part per billion). All of these mean the parent compound is available to the brain. The higher the level, the more drug ingested or the more recently the drug was used. Delta 9 THC has been measured in oral fluid up to 72 hours after smoking.

Urine THC

11 nor 9 carboxy THC is the major metabolite found in urine. A single dose of THC may be detected in urine for an average of 24 to 120 hours. In most peer-reviewed papers, the highest doses produced positive screens for up to 120 hours, with most papers reporting an average of 26 to 33 hours. Urine excretion of THC does not decrease consistently so urine screenings may fluctuate between negative and positive during the detection window.

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